Contrast agents for myocardial perfusion imaging

ABSTRACT

The present disclosure is directed, in part, to compounds and methods for imaging myocardial perfusion, comprising administering to a patient a contrast agent which comprises a compound that binds MC-1, and an imaging moiety, and scanning the patient using diagnostic imaging.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation and claims priority toco-pending U.S. application Ser. No. 13/529,756, filed Jun. 21, 2012,which is a continuation of U.S. application Ser. No. 12/014,161, filedJan. 15, 2008, which is a divisional application of U.S. applicationSer. No. 11/055,498, filed Feb. 10, 2005, which claims the benefit ofU.S. Provisional Application Ser. No. 60/544,861, filed Feb. 13, 2004,each of which are herein incorporated by reference.

CONTRAST AGENTS FOR MYOCARDIAL PERFUSION IMAGING

The present disclosure relates to novel compounds comprising imagingmoieties, and their use for diagnosing certain disorders in a patient.

Mitochondria are membrane-enclosed organelles distributed through thecytosol of most eukaryotic cells. Mitochondria are especiallyconcentrated in myocardium tissue.

Complex 1 (“MC-1”) is a membrane-bound protein complex of 46 dissimilarsubunits. This enzyme complex is one of three energy-transducingcomplexes that constitute the respiratory chain in mammalianmitochondria. This NADH-ubiquinone oxidoreductase is the point of entryfor the majority of electrons that traverse the respiratory chain,eventually resulting in the reduction of oxygen to water (Q. Rev.Biophys. 1992, 25, 253-324).

Known inhibitors of MC-1 include deguelin, piericidin A, ubicidin-3,rolliniastatin-1, rolliniastatin-2 (bullatacin), capsaicin, pyridaben,fenpyroximate, amytal, MPP+, quinolines, and quinolones (BBA 1998, 1364,222-235).

The present disclosure is based, in part, on the recognition thatinterrupting the normal function of mitochondria could advantageouslyconcentrate certain compounds in the mitochondria, and hence in themitochondria-rich myocardium tissue. If these compounds were labeledwith an imaging moiety, such a build up could be detected, therebyproviding valuable diagnostic markers for myocardial perfusion imaging.For purposes of this specification, a compound is referred to as“labeled” when an imaging moiety is attached to the compound.

In one embodiment the present disclosure provides a method of imagingmyocardial perfusion comprising administering to a patient a contrastagent which comprises an imaging moiety and a compound selected fromdeguelin, pyridaben, pyridimifen, tebufenpyrad, fenazaquin, a deguelinanalog, a pyridaben analog, a pyridimifen analog, a tebufenpyrad analog,and an fenazaquin analog; and scanning the patient using diagnosticimaging. In another embodiment the imaging moiety is a radioisotope fornuclear medicine imaging, a paramagnetic species for use in MRI imaging,an echogenic entity for use in ultrasound imaging, a fluorescent entityfor use in fluorescence imaging, or a light-active entity for use inoptical imaging.

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog. In another embodiment the imaging moiety is aradioisotope for nuclear medicine imaging, a paramagnetic species foruse in MRI imaging, an echogenic entity for use in ultrasound imaging, afluorescent entity for use in fluorescence imaging, or a light-activeentity for use in optical imaging.

In another embodiment the paramagnetic species for use in MRI imaging isGd³⁺, Fe³⁺, In³⁺, or Mn²⁺.

In another embodiment the echogenic entity for use in ultrasound imagingis a fluorocarbon encapsulated surfactant microsphere.

In another embodiment the radioisotope for nuclear medicine imaging is¹¹C, ¹³N, ¹⁸F, ¹²³I, ¹²⁵I, ^(99m)Tc, ⁹⁵Tc, ¹¹¹In, ⁶²Cu, ⁶⁴Cu, ⁶⁷Ga, or⁶⁸Ga. In another embodiment the imaging moiety is ¹⁸F. In anotherembodiment the imaging moiety is ^(99m)Tc.

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (I)

wherein

each A is independently selected from O, CHR¹, S, and NR¹;

B is selected from hydrogen, C₁-C₆ alkyl optionally substituted with animaging moiety, and an imaging moiety;

C is selected from hydrogen, C₁-C₆ alkyl optionally substituted with animaging moiety, an imaging moiety, and a bond to B;

D is selected from hydrogen, C₁-C₆ alkyl optionally substituted with animaging moiety, and an imaging moiety;

E is selected from hydrogen, C₁-C₆ alkyl optionally substituted with animaging moiety, and an, imaging moiety; or

E and D, together with the carbon atom to which they are attached, forma double bond; or

E and D, together with the carbon atom to which they are attached, forma cyclopropyl ring;

is a single or a double bond;

R¹, R², R³, R⁴, R⁹, R¹⁰, R¹³, and R¹⁴, are each independently selectedfrom hydrogen, C₁-C₆ alkyl optionally substituted with an imagingmoiety, and an imaging moiety;

R⁵ and R⁶ are each independently selected from hydrogen, C₁-C₆ alkyloptionally substituted with an imaging moiety, halo, hydroxy, and animaging moiety;

when present, R⁷ and R⁸ are independently selected from hydrogen, C₁-C₆alkyl optionally substituted with an imaging moiety, halo, hydroxy, andan imaging moiety; or

R⁵ and R⁷ together form an oxo group; or

R⁶ and R⁸ together form an oxo group; or

R⁷ is O and R⁸ is a bond to R7;

provided that when

is a double bond, R⁷ and R⁸ are absent;

R¹¹ is hydrogen or hydroxy;

R¹² is selected from hydrogen, C₁-C₆ alkyl optionally substituted withan imaging moiety, and an imaging moiety; or

R¹¹ and R¹² together form an oxo group or ═CHR¹;

with the proviso that at least one imaging moiety is present in formula(I).

In another embodiment

A is O;

B and C are each independently CH₃ or CH₂ ¹⁸F;

D and E are each independently CH₃ or CH₂ ¹⁸F;

R⁵, R⁶, R⁹, and R¹⁰ are each independently hydrogen or ¹⁸F; and

R¹¹ and R¹² together form an oxo group.

In another embodiment the contrast agent is selected from

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (II),

wherein

G is

wherein

-   -   m is 0 or 1;    -   and        each independently represent a single or a double bond;    -   R²⁷, R³⁰, R³¹, R³², R³³, and R³⁴ are independently selected from        hydrogen, C₁-C₆ alkyl optionally substituted with an imaging        moiety, and an imaging moiety;    -   when present, R²⁸ is selected from hydrogen and C₁-C₆ alkyl        optionally substituted with an imaging moiety, provided that        when        is a double bond, R²⁸ is absent;    -   when present, R²⁹ is C₁-C₆ alkyl optionally substituted with an        imaging moiety, provided that when        is a double bond, R²⁹ is absent;    -   P is

wherein R³⁵, R³⁶, R³⁷, R³⁸, and R³⁹ are independently selected fromhydrogen, C₁-C₆ alkyl optionally substituted with an imaging moiety, andan imaging moiety;

-   -   when present, P′ is hydrogen; or    -   P and P′ together form an oxo group;    -   provided that when        is a double bond, P′ is absent;    -   Q is halo or haloalkyl;

J is selected from N(R²⁷), S, O, C(═O), C(═O)O, NHCH₂CH₂O, a bond, andC(═O)N(R²⁷), with each group being drawn with its left end attached to Gand its right end attached to the carbon substituted with R²¹ and R²²;

when present, K is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

when present, L is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

M is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl, C₁-C₆ alkyloptionally substituted with an imaging moiety, heteroaryl, and animaging moiety; or

L and M, together with the atom to which they are attached, form athree- or four-membered carbocyclic ring;

n is 0, 1, 2, or 3;

R²¹, R²², R²³, R²⁴, R²⁵, and R²⁶ are independently selected fromhydrogen, C₁-C₆ alkyl optionally substituted with an imaging moiety, andan imaging moiety; and

Y is selected from a bond, carbon, and oxygen; provided that when Y is abond, K and L are absent and M is selected from aryl and heteroaryl; andprovided that when Y is oxygen, K and L are absent and M is selectedfrom hydrogen, alkoxyalkyl, aryl, C₁-C₆ alkyl optionally substitutedwith an imaging moiety, and heteroaryl;

provided that at least one imaging moiety is present in formula (II).

In another embodiment R²⁹ is C₁-C₆ alkyl wherein the C₁-C₆ alkyl istert-butyl.

In another embodiment R²⁸ is C₁-C₆ alkyl wherein the C₁-C₆ alkyl ismethyl.

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (III)

wherein:

J is selected from N(R²⁷), S, O, C(═O), C(═O)O, NHCH₂CH₂O, a bond, orC(═O)N(R²⁷), with each group being drawn with its left end attached to Gand its right end attached to the carbon substituted with R²¹ and R²²;

when present, K is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

when present, L is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

M is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl, C₁-C₆ alkyloptionally substituted with an imaging moiety, heteroaryl, and animaging moiety; or

L and M, together with the atom to which they are attached, form athree- or four-membered carbocyclic ring;

Q is halo or haloalkyl;

n is 0, 1, 2, or 3;

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, and R²⁷ are independently selected fromhydrogen, C₁-C₆ alkyl optionally substituted with an imaging moiety, andan imaging moiety;

R²⁹ is C₁-C₆ alkyl optionally substituted with an imaging moiety; and

Y is selected from a bond, carbon, and oxygen; provided that when Y is abond, K and L are absent and M is selected from aryl and heteroaryl; andprovided that when Y is oxygen, K and L are absent and M is selectedfrom hydrogen, alkoxyalkyl, aryl, C₁-C₆ alkyl optionally substitutedwith an imaging moiety, and heteroaryl;

provided that at least one imaging moiety is present in formula (III).

In another embodiment J is O and R²⁹ is C₁-C₆ alkyl wherein the C₁-C₆alkyl is tert-butyl.

In another embodiment the contrast agent is selected from

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (IV):

wherein:

J is selected from N(R²⁷), S, O, C(═O), C(═O)O, NHCH₂CH₂O, a bond, andC(═O)N(R²⁷), with each group being drawn with its left end attached to Gand its right end attached to the carbon substituted with R²¹ and R²²;

when present, K is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

L is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl, C₁-C₆ alkyloptionally substituted with an imaging moiety, heteroaryl, and animaging moiety;

M is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl, C₁-C₆ alkyloptionally substituted with an imaging moiety, heteroaryl, and animaging moiety; or

L and M, together with the atom to which they are attached, form athree- or four-membered carbocyclic ring;

Q is halo or haloalkyl;

n is 0, 1, 2, or 3;

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R²⁸, R³⁵, R³⁶, R³⁷, R³⁸, and R³⁹ areindependently selected from hydrogen, C₁-C₆ alkyl optionally substitutedwith an imaging moiety, and an imaging moiety; and

Y is selected from a bond, carbon, and oxygen, provided that when Y is abond, K and L are absent and M is selected from aryl and heteroaryl; andprovided that when Y is oxygen, K and L are absent and M is selectedfrom hydrogen, alkoxyalkyl, aryl, C₁-C₆ alkyl optionally substitutedwith an imaging moiety, and heteroaryl;

provided that at least one imaging moiety is present in formula (IV).

In another embodiment J is C(═O)N(H), and R²⁸ is C₁-C₆ alkyl wherein theC₁-C₆ alkyl is methyl.

In another embodiment the contrast agent is selected from

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (V)

wherein

J is selected from N(R²⁷), S, O, C(═O), C(═O)O, NHCH₂CH₂O, a bond, andC(═O)N(R²⁷);

K is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl, C₁-C₆ alkyloptionally substituted with an imaging moiety, heteroaryl, and animaging moiety;

when present, L is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety;

when present, M is selected from hydrogen, alkoxyalkyl, alkyloxy, aryl,C₁-C₆ alkyl optionally substituted with an imaging moiety, heteroaryl,and an imaging moiety; or

L and M, together with the atom to which they are attached, form athree- or four-membered carbocyclic ring;

T and U are independently selected from hydrogen, alkoxy, alkoxyalkyl,C₁-C₆ alkyl optionally substituted with an imaging moiety, halo, and animaging moiety; or

T and U, together with the carbon atoms to which they are attached, forma five- to six-membered aromatic or non-aromatic ring containing zero totwo heteroatoms selected from oxygen, nitrogen, and sulfur; wherein saidring is optionally substituted with one, two, or three substituentsindependently selected from C₁-C₆ alkyl optionally substituted with animaging moiety and an imaging moiety;

-   -   n is 0, 1, 2, or 3; and

R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, and R³⁴ are independently selectedfrom hydrogen, C₁-C₆ alkyl optionally substituted with an imagingmoiety, and an imaging moiety;

Y is selected from a bond, carbon, and oxygen, provided that when Y is abond, K and L are absent and M is selected from aryl and heteroaryl; andprovided that when Y is oxygen, K and L are absent and M is selectedfrom hydrogen, alkoxyalkyl, aryl, C₁-C₆ alkyl optionally substitutedwith an imaging moiety, and heteroaryl;

provided at least one imaging moiety is present in formula (V).

In another embodiment J is O.

In another embodiment the present disclosure provides a contrast agentcomprising an imaging moiety and a compound selected from deguelin,pyridaben, pyridimifen, tebufenpyrad, fenazaquin a deguelin analog, apyridaben analog, a pyridimifen analog, a tebufenpyrad analog, and anfenazaquin analog wherein the contrast agent is of formula (VI)

wherein

R²³, R²⁴, R²⁵, R²⁶, and R³⁴ are independently selected from hydrogen,C₁-C₆ alkyl optionally substituted with an imaging moiety, and animaging moiety;

provided that at least one imaging moiety is present in formula (VI).

In another embodiment the contrast agent is selected from

Imaging Moieties

Nuclear medicine contrast agents of the present disclosure include ¹¹C,¹³N, ¹⁸F, ¹²³I, ¹²⁵I, ^(99m)Tc, ⁹⁵Tc, ¹¹¹In, ⁶²Cu, ⁶⁴Cu, ⁶⁷Ga, and ⁶⁸Ga.¹¹C-Palmitate has been used to probe fatty acid oxidation and¹¹C-acetate has been used to assess oxidative metabolism in themyocardium (Circulation 1987, 76, 687-696). ¹³N-Ammonia has been usedwidely to image myocardial perfusion (Circulation 1989, 80, 1328-37).Agents based on ¹⁸F have been used as imaging agents for hypoxia andcancer (Drugs of the Future 2002, 27, 655-667).15-(p-(¹²³I-iodophenyl)-pentadecanoic acid and15-(p-(¹²³I)-iodophenyl)-3(R,S)-methylpentadecanoic acid are twoiodinated agents that have been used for imaging myocardial metabolism.In one embodiment, the imaging moiety employed in the present contrastagents is ¹⁸F. Further imaging moieties of the present disclosure may becomprised of one or more X-ray absorbing or “heavy” atoms of atomicnumber 20 or greater, further comprising an optional linking moiety, L,between the parent molecular moiety and the X-ray absorbing atoms. Afrequently used heavy atom in X-ray contrast agents is iodine. Recently,X-ray contrast agents comprised of metal chelates (U.S. Pat. No.5,417,959) and polychelates comprised of a plurality of metal ions (U.S.Pat. No. 5,679,810) have been disclosed. More recently, multinuclearcluster complexes have been disclosed as X-ray contrast agents (U.S.Pat. No. 5,804,161, WO 91/14460, and WO 92/17215). In certainembodiments of the present disclosure the specific metals used in theX-ray contrast agents include Re, Sm, Ho, Lu, Pm, Y, Bi, Pd, Gd, La, Au,Au, Yb, Dy, Cu, Rh, Ag, and Ir.

MRI contrast agents of the present disclosure may be comprised of one ormore analog moieties attached to one or more paramagnetic metal ions,further comprising an optional linking moiety, L, between the analogmoieties and the paramagnetic metal ions. The paramagnetic metal ionsmay be present in the form of metal chelates or complexes or metal oxideparticles. U.S. Pat. Nos. 5,412,148, and 5,760,191, describe examples ofchelators for paramagnetic metal ions for use in MRI contrast agents.U.S. Pat. No. 5,801,228, U.S. Pat. No. 5,567,411, and U.S. Pat. No.5,281,704, describe examples of polychelants useful for complexing morethan one paramagnetic metal ion for use in MRI contrast agents. U.S.Pat. No. 5,520,904, describes particulate compositions comprised ofparamagnetic metal ions for use as MRI contrast agents. Examples ofspecific metals include Gd³⁺, Fe³⁺, In³⁺, and Mn²⁺.

The ultrasound contrast agents of the present disclosure may comprise aplurality of analog moieties attached to or incorporated into amicrobubble of a biocompatible gas, a liquid carrier, and a surfactantmicrosphere, further comprising an optional linking moiety, L, betweenthe analog moieties and the microbubble. In this context, the term“liquid carrier” means aqueous solution and the term “surfactant” meansany amphiphilic material which may produce a reduction in interfacialtension in a solution. A list of suitable surfactants for formingsurfactant microspheres is disclosed, for example, in EP0727225A2. Theterm “surfactant microsphere” includes microspheres, nanospheres,liposomes, vesicles and the like. The biocompatible gas can be anyphysiologically accepted gas, including, for example, air, or afluorocarbon, such as a C₃-C₅ perfluoroalkane, which provides thedifference in echogenicity and thus the contrast in ultrasound imaging.The gas may be encapsulated, contained, or otherwise constrained in orby the microsphere to which is attached the analog moiety, optionallyvia a linking group. The attachment can be covalent, ionic or by van derWaals forces. Specific examples of such contrast agents include, forexample, lipid encapsulated perfluorocarbons with a plurality of tumorneovasculature receptor binding peptides, polypeptides orpeptidomimetics. Examples of gas filled imaging moieties include thosefound in U.S. patent application Ser. No. 09/931,317, filed Aug. 16,2001, and U.S. Pat. Nos. 5,088,499, 5,547,656, 5,228,446, 5,585,112, and5,846,517.

Chelators

Many approaches to labeling compounds with ^(99m)Tc are known, includingdirect labeling of the compound or inclusion of a chelating moiety(“chelator”). In one embodiment, the chelator is DADT, MAG3, MAMA, PAMA,or DOTA.

The compounds of the disclosure may optionally contain a chelator (“C”).In certain embodiments of the compounds of the disclosure, the chelatoris a surfactant capable of forming an echogenic substance-filled lipidsphere or microbubble. In certain other embodiments, the chelator is abonding unit having a formula selected from

andwherein

each A¹ is independently selected from —NR⁴⁶R⁴⁷, —NHR⁵³, —SH, —S(Pg),—OH, —PR⁴⁶R⁴⁷, —P(O)R⁴⁸R⁴⁹, and a bond to the compound that binds MC-1;

each A² is independently selected from N(R⁵³), N(R⁴⁶), S, O, P(R⁴⁶), and—OP(O)(R⁴⁸)O—;

A³ is N;

A⁴ is selected from OH and OC(═O)C₁-C₂₀ alkyl;

A⁵ is OC(═O) C₁-C₂₀ alkyl;

each E is independently selected from C₁-C₁₆ alkylene substituted with0-3 R⁵⁰, C₆-C₁₀ arylene substituted with 0-3 R⁵⁰, C₃-C₁₀ cycloalkylenesubstituted with 0-3 R⁵⁰, heterocyclyl-C₁-C₁₀ alkylene substituted with0-3 R⁵⁰, C₆-C₁₀ aryl-C₁-C₁₀ alkylene substituted with 0-3 R⁵⁰, andheterocyclylene substituted with 0-3 R⁵⁰;

E¹ is selected from a bond and E;

each E² is independently selected from C₁-C₁₆ alkyl substituted with 0-3R⁵⁰, C₆-C₁₀ aryl substituted with 0-3 R⁵⁰, C₃-C₁₀ cycloalkyl substitutedwith 0-3 R⁵⁰, heterocyclyl-C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, C₆-C₁₀aryl-C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, C₁-C₁₀ alkyl-C₆-C₁₀ arylsubstituted with 0-3 R⁵⁰, and heterocyclyl substituted with 0-3 R⁵⁰;

E³ is C₁-C₁₀ alkylene substituted with 1-3 R⁵⁹;

Pg is a thiol protecting group;

R⁴⁶ and R⁴⁷ are each independently selected from a bond to the compoundthat binds MC-1, hydrogen, C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, arylsubstituted with 0-3 R⁵⁰, C₃-C₁₀ cycloalkyl substituted with 0-3 R⁵⁰,heterocyclyl-C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, C₆-C₁₀ aryl-C₁-C₁₀alkyl substituted with 0-3 R⁵⁰, and heterocyclyl substituted with 0-3R⁵⁰;

R⁴⁸ and R⁴⁹ are each independently selected from a bond to the compoundthat binds MC-1, —OH, C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, arylsubstituted with 0-3 R⁵⁰, C₃-C₁₀ cycloalkyl substituted with 0-3 R⁵⁰,heterocyclyl-C₁-C₁₀ alkyl substituted with 0-3 R⁵⁰, C₆-C₁₀ aryl-C₁-C₁₀alkyl substituted with 0-3 R⁵⁰, and heterocyclyl substituted with 0-3R⁵⁰;

each R⁵⁰ is independently selected from a bond to the compound thatbinds MC-1, ═O, halo, trifluoromethyl, cyano, —CO₂R⁵¹, —C(═O)R⁵¹,—C(═O)N(R⁵¹)₂, —CHO, —CH₂OR⁵¹,

—OC(═O)R⁵¹, —OC(═O)OR⁵¹, —OR⁵¹, —OC(═O)N(R⁵¹)₂, —NR⁵¹C(═O)R⁵¹,—NR⁵¹C(═O)OR⁵¹,

—NR⁵¹C(═O)N(R⁵¹)₂, —NR⁵¹SO₂N(R⁵¹)₂, —NR⁵¹SO₂R⁵¹, —SO₃H, —SO₂R⁵¹,

—SR⁵¹, —S(═O)R⁵¹, —SO₂N(R⁵¹)₂, —N(R⁵¹)₂, —NHC(═S)NHR⁵¹, ═NOR⁵¹, NO₂,—C(═O)NHOR⁵¹, —C(═O)NHN(R⁵¹)₂, —OCH₂CO₂H, 2-(1-morpholino)ethoxy, C₁-C₅alkyl, C₂-C₄ alkenyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₂-C₆alkoxyalkyl, aryl substituted with 0-2 R⁵¹, and heterocyclyl;

each R⁵¹ is independently selected from a bond to the compound thatbinds MC-1, hydrogen, C₁-C₆ alkyl, phenyl, benzyl, and C₁-C₆ alkoxy;

R⁵³ is a co-ordinate bond to a metal;

each R⁵⁹ selected from R⁶¹, ═O, —CO₂R⁶⁰, —C(═O)R⁶⁰, —C(═O)N(R⁶)₂,—CH₂OR⁶⁰,

—OR⁶⁰, —N(R⁶⁰)₂, and C₂-C₄ alkenyl;

each R⁶⁰ is independently selected from R⁶¹, hydrogen, C₁-C₆ alkyl,phenyl, benzyl, and trifluoromethyl; and

R⁶¹ is a bond to the compound that binds MC-1;

wherein at least one of A¹, R⁴⁶, R⁴⁷, R⁴⁸, R⁴⁹, R⁵⁰, R⁵¹, and R⁶¹ is abond to the compound that binds MC-1.

Methods of Making

Typically ¹⁸F labeled compounds are synthesized by S_(n)2 displacementof an appropriate leaving group. These leaving groups are preferrablysulfonic acid esters such as toluenesulfonate (tosylate, TsO),methanesulfonate (mesylate, MsO), or trifluoromethanesulfonate(triflate, TfO). The leaving group may also be a halide, aphosphineoxide (via Mitsunobu reaction), or an internal leaving group(such as an epoxide or cyclic sulfate). These compounds are made fromhighly activated, dry K¹⁸F, that is made “hotter” by the addition ofcryptands such as krytofix[2.2.2]. Purification is generally via saltremoval by reverse-phase chromatography (Sep-Pak).

Representative methods of making the contrast agents are described inthe following examples. The foregoing chemical transformations may beconducted using techniques which would be readily apparent to one ofordinary skill in the art, once armed with the teachings in the presentapplications. Representative reaction solvents include, for example,DMF, NMP, DMSO, THF, ethyl acetate, dichloromethane, and chloroform. Thereaction solution may be kept neutral or basic by the addition of anamine such as triethylamine or DIEA. Reactions may be carried out atambient temperatures and protected from oxygen and water with a nitrogenatmosphere.

Temporary protecting groups may be used to prevent other reactivefunctionality, such as amines, thiols, alcohols, phenols, and carboxylicacids, from participating in the reaction. Representative amineprotecting groups include, for example, tert-butoxycarbonyl and trityl(removed under mild acidic conditions), Fmoc (removed by the use ofsecondary amines such as piperidine), and benzyloxycarbonyl (removed bystrong acid or by catalytic hydrogenolysis). The trityl group may alsoused for the protection of thiols, phenols, and alcohols. In certainembodiments the carboxylic acid protecting groups include, for example,tert-butyl ester (removed by mild acid), benzyl ester (usually removedby catalytic hydrogenolysis), and alkyl esters such as methyl or ethyl(usually removed by mild base). All protecting groups may be removed atthe conclusion of synthesis using the conditions described above for theindividual protecting groups, and the final product may be purified bytechniques which would be readily apparent to one of ordinary skill inthe art, once armed with the present disclosure.

Use

The contrast agents of the present disclosure may be used in a method ofimaging, including methods of imaging in a patient comprisingadministering the contrast agent to the patient by injection, infusion,or any other known method, and imaging the area of the patient whereinthe event of interest is located.

The useful dosage to be administered and the particular mode ofadministration will vary depending upon such factors as age, weight, andparticular region to be treated, as well as the particular contrastagent used, the diagnostic use contemplated, and the form of theformulation, for example, suspension, emulsion, microsphere, liposome,or the like, as will be readily apparent to those skilled in the art.

Typically, dosage is administered at lower levels and increased untilthe desirable diagnostic effect is achieved. In one embodiment, theabove-described contrast agents may be administered by intravenousinjection, usually in saline solution, at a dose of about 0.1 to about100 mCi per 70 kg body weight (and all combinations and subcombinationsof dosage ranges and specific dosages therein), or preferably at a doseof about 0.5 to about 50 mCi. Imaging is performed using techniques wellknown to the ordinarily skilled artisan.

For use as nuclear medicine contrast agents, the compositions of thepresent disclosure, dosages, administered by intravenous injection, willtypically range from about 0.5 μmol/kg to about 1.5 mmol/kg (and allcombinations and subcombinations of dosage ranges and specific dosagestherein), preferably about 0.8 μmol/kg to about 1.2 mmol/kg.

For use as MRI contrast agents, the compositions of the presentdisclosure may be used in a similar manner as other MRI agents asdescribed in U.S. Pat. No. 5,155,215; U.S. Pat. No. 5,087,440; Magn.Reson. Med. 1986, 3, 808; Radiology 1988, 166, 835; and Radiology 1988,166, 693. Generally, sterile aqueous solutions of the contrast agentsmay be administered to a patient intravenously in dosages ranging fromabout 0.01 to about 1.0 mmoles per kg body weight (and all combinationsand subcombinations of dosage ranges and specific dosages therein).

The ultrasound contrast agents of the present disclosure may beadministered by intravenous injection in an amount from about 10 toabout 30 μL (and all combinations and subcombinations of dosage rangesand specific dosages therein) of the echogenic gas per kg body weight orby infusion at a rate of approximately 3 μL/kg/min.

Another aspect of the present disclosure is diagnostic kits for thepreparation of diagnostic agents for detecting, imaging, and/ormonitoring myocardial perfusion. Diagnostic kits of the presentdisclosure comprise one or more vials containing the sterile,non-pyrogenic, formulation comprising a predetermined amount of areagent of the present disclosure, and optionally other components suchas one or two ancillary ligands such as tricine and3-[bis(3-sulfophenyl)phosphine]benzenesulfonic acid (TPPTS), reducingagents, transfer ligands, buffers, lyophilization aids, stabilizationaids, solubilization aids and bacteriostats. The kits may also comprisea reducing agent, such as, for example, tin(II).

Buffers useful in the preparation of contrast agents and kits include,for example, phosphate, citrate, sulfosalicylate, and acetate buffers. Amore complete list can be found in the United States Pharmacopoeia.

Lyophilization aids useful in the preparation of contrast agents andkits include, for example, mannitol, lactose, sorbitol, dextran, FICOLL®polymer, and polyvinylpyrrolidine (PVP).

Stabilization aids useful in the preparation of contrast agents and kitsinclude, for example, ascorbic acid, cysteine, monothioglycerol, sodiumbisulfite, sodium metabisulfite, gentisic acid, and inositol.

Solubilization aids useful in the preparation of contrast agents andkits include, for example, ethanol, glycerin, polyethylene glycol,propylene glycol, polyoxyethylene sorbitan monooleate, sorbitanmonoloeate, polysorbates,poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) block copolymers(“Pluronics”) and lecithin. In certain embodiments the solubilizing aidsare polyethylene glycol and Pluronics.

Bacteriostats useful in the preparation of contrast agents and kitsinclude, for example, benzyl alcohol, benzalkonium chloride,chlorbutanol, and methyl, propyl, or butyl paraben.

A component in a diagnostic kit can also serve more than one function.For example, a reducing agent for a radionuclide can also serve as astabilization aid, or a buffer can also serve as a transfer ligand, or alyophilization aid can also serve as a transfer, ancillary, orco-ligand.

The compounds herein described may have asymmetric centers. Unlessotherwise indicated, all chiral, diastereomeric and racemic forms areincluded in the present disclosure. Many geometric isomers of olefins,C═N double bonds, and the like can also be present in the compoundsdescribed herein, and all such stable isomers are contemplated in thepresent disclosure. It will be appreciated that compounds of the presentdisclosure may contain asymmetrically substituted carbon atoms, and maybe isolated in optically active or racemic forms. It is well known inthe art how to prepare optically active forms, such as by resolution ofracemic forms or by synthesis from optically active starting materials.Two distinct isomers (cis and trans) of the peptide bond are known tooccur; both can also be present in the compounds described herein, andall such stable isomers are contemplated in the present disclosure. TheD- and L-isomers of a particular amino acid are designated herein usingthe conventional 3-letter abbreviation of the amino acid, as indicatedby the following examples: D-Leu, or L-Leu.

For the sake of simplicity, connection points (“−”) are not depicted.When an atom or compound is described to define a variable, it isunderstood that it is intended to replace the variable in a manner tosatisfy the valency of the atom or compound. For example, if a variableA″ was identified as C(R⁸⁰)═C(R⁸⁰), both carbon atoms would form a partof the chain in order to satisfy their respective valences.

When any variable occurs more than one time in any substituent or in anyformula, its definition in each occurrence is independent of itsdefinition at every other occurrence. Thus, for example, if a group, orplurality of groups, is shown to be substituted with 0-2 R⁸⁰, then saidgroup(s) may optionally be substituted with up to two R⁸⁰, and R⁸⁰ ateach occurrence in each group is selected independently from the definedlist of possible R⁸⁰. Also, by way of example, for the group —N(R⁸¹)₂,each of the two R⁸¹ substituents on N is independently selected from thedefined list of possible R⁸¹. Combinations of substituents and/orvariables are permissible only if such combinations result in stablecompounds. When a bond to a substituent is shown to cross the bondconnecting two atoms in a ring, then such substituent may be bonded toany atom on the ring.

DEFINITIONS

The number of carbon atoms in any particular group is denoted before therecitation of the group. For example, the term “C₆-C₁₀aryl” denotes anaryl group containing from six to ten carbon atoms, and the term“C₆-C₁₀aryl-C₁-C₁₀alkyl,” refers to an aryl group of six to ten carbonatoms attached to the parent molecular moiety through an alkyl group ofone to ten carbon atoms.

The term “alkenyl,” as used herein, refers to a straight or branchedchain hydrocarbon containing at least one carbon-carbon double bond.

The term “alkoxy,” as used herein, refers to a C₁-C₆ alkyl groupattached to the parent molecular moiety through an oxygen atom.

The term “alkoxyalkyl,” as used herein, refers to a C₁-C₆ alkyl groupsubstituted with one, two, or three alkoxy groups.

The term “alkyl,” as used herein, refers to a group derived from astraight or branched chain saturated hydrocarbon.

The term “alkylaryl,” as used herein, refers to an alkyl group attachedto the parent molecular moiety through an aryl group.

The term “alkylene,” as used herein, refers to a divalent group derivedfrom a straight or branched chain saturated hydrocarbon.

The term “alkyloxy,” as used herein, refers to a C₁-C₆ alkyl groupattached to the parent molecular moiety through an oxygen atom.

The term “analog moiety,” as used herein, refers to the compounds of thepresent disclosure excluding the imaging moiety or moieties.

The term “aryl,” as used herein, refers to a phenyl group, or a bicyclicfused ring system wherein one or more of the rings is a phenyl group.Bicyclic fused ring systems consist of a phenyl group fused to amonocyclic cycloalkenyl group, a monocyclic cycloalkyl group, or anotherphenyl group. The aryl groups of the present invention can be attachedto the parent molecular moiety through any substitutable carbon atom inthe group. Representative examples of aryl groups include, but are notlimited to, anthracenyl, azulenyl, fluorenyl, indanyl, indenyl,naphthyl, phenyl, and tetrahydronaphthyl.

The term “arylalkyl,” as used herein, refers to an alkyl groupsubstituted with one, two, or three aryl groups.

The term “arylalkylene,” as used herein, refers to a divalent arylalkylgroup, where one point of attachment to the parent molecular moiety ison the aryl portion and the other is on the alkyl portion.

The term “arylene,” as used herein, refers to a divalent aryl group.

As used herein, the terms “ancillary” or “co-ligands” refers to ligandsthat serve to complete the coordination sphere of the radionuclidetogether with the chelator or radionuclide bonding unit of the reagent.For radiopharmaceuticals comprising a binary ligand system, theradionuclide coordination sphere comprises one or more chelators orbonding units from one or more reagents and one or more ancillary orco-ligands, provided that there are a total of two types of ligands,chelators or bonding units. For example, a radiopharmaceutical comprisedof one chelator or bonding unit from one reagent and two of the sameancillary or co-ligands and a radiopharmaceutical comprising twochelators or bonding units from one or two reagents and one ancillary orco-ligand are both considered to comprise binary ligand systems. Forradiopharmaceuticals comprising a ternary ligand system, theradionuclide coordination sphere comprises one or more chelators orbonding units from one or more reagents and one or more of two differenttypes of ancillary or co-ligands, provided that there are a total ofthree types of ligands, chelators or bonding units. For example, aradiopharmaceutical comprised of one chelator or bonding unit from onereagent and two different ancillary or co-ligands is considered tocomprise a ternary ligand system.

Ancillary or co-ligands useful in the preparation ofradiopharmaceuticals and in diagnostic kits useful for the preparationof said radiopharmaceuticals comprise one or more oxygen, nitrogen,carbon, sulfur, phosphorus, arsenic, selenium, and tellurium donoratoms. A ligand can be a transfer ligand in the synthesis of aradiopharmaceutical and also serve as an ancillary or co-ligand inanother radiopharmaceutical. Whether a ligand is termed a transfer orancillary or co-ligand depends on whether the ligand remains in theradionuclide coordination sphere in the radiopharmaceutical, which isdetermined by the coordination chemistry of the radionuclide and thechelator or bonding unit of the reagent or reagents.

A “bacteriostat” is a component that inhibits the growth of bacteria ina formulation either during its storage before use of after a diagnostickit is used to synthesize a radiopharmaceutical.

The term “bubbles” or “microbubbles,” as used herein, refers to vesicleswhich are generally characterized by the presence of one or moremembranes or walls surrounding an internal void that is filled with agas or precursor thereto. Exemplary bubbles or microbubbles include, forexample, liposomes, micelles, and the like.

The terms “chelator” and “bonding unit,” as used herein, refer to themoiety or group on a reagent that binds to a metal ion through one ormore donor atoms.

The term “contrast agent,” as used herein, refers to an agent used tohighlight specific areas so that organs, blood vessels, and/or tissuesare more visible. By increasing the visibility of the surfaces beingstudied, the presence and extent of disease and/or injury can bedetermined.

The term “cycloalkenyl,” as used herein, refers to a non-aromatic,partially unsaturated monocyclic, bicyclic, or tricyclic ring systemhaving three to fourteen carbon atoms and zero heteroatoms.Representative examples of cycloalkenyl groups include, but are notlimited to, cyclohexenyl, octahydronaphthalenyl, and norbomylenyl.

The term “cycloalkyl,” as used herein, refers to a saturated monocyclic,bicyclic, or tricyclic hydrocarbon ring system having three to fourteencarbon atoms and zero heteroatoms. Representative examples of cycloalkylgroups include, but are not limited to, cyclopropyl, cyclopentyl,bicyclo[3.1.1]heptyl, and adamantyl.

The term “C₃-C₁₀ cycloalkylene,” as used herein, refers to a divalentcycloalkyl group containing from three to ten carbon atoms.

The term “diagnostic imaging,” as used herein, refers to a procedureused to detect a contrast agent.

A “diagnostic kit” or “kit” comprises a collection of components, termedthe formulation, in one or more vials which are used by the practicingend user in a clinical or pharmacy setting to synthesize diagnosticradiopharmaceuticals. The kit preferably provides all the requisitecomponents to synthesize and use the diagnostic pharmaceutical exceptthose that are commonly available to the practicing end user, such aswater or saline for injection, a solution of the radionuclide, equipmentfor heating the kit during the synthesis of the radiopharmaceutical, ifrequired, equipment necessary for administering the radiopharmaceuticalto the patient such as syringes, shielding, imaging equipment, and thelike. Contrast agents are provided to the end user in their final formin a formulation contained typically in one vial, as either alyophilized solid or an aqueous solution. The end user typicallyreconstitutes the lyophilized material with water or saline andwithdraws the patient dose or just withdraws the dose from the aqueoussolution formulation as provided.

The term “donor atom,” as used herein, refers to the atom directlyattached to a metal by a chemical bond.

The terms “halo” and “halogen,” as used herein, refer to F, Cl, Br, orI.

The term “haloalkyl,” as used herein, refers to a C₁-C₆ alkyl groupsubstituted by one, two, three, or four halogen atoms.

The term “heteroaryl,” as used herein, refers to an aromatic five- orsix-membered ring where at least one atom is selected from N, O, and S,and the remaining atoms are carbon. The term “heteroaryl” also includesbicyclic systems where a heteroaryl ring is fused to a four- tosix-membered aromatic or non-aromatic ring containing zero, one, or twoadditional heteroatoms selected from N, O, and S. The heteroaryl groupsare attached to the parent molecular moiety through any substitutablecarbon or nitrogen atom in the group. Representative examples ofheteroaryl groups include, but are not limited to, benzoxadiazolyl,benzoxazolyl, benzofuranyl, benzothienyl, furanyl, imidazolyl,indazolyl, indolyl, isoxazolyl, isoquinolinyl, isothiazolyl,naphthyridinyl, oxadiazolyl, oxazolyl, pyridinyl, pyridazinyl,pyrimidinyl, pyrazinyl, pyrazolyl, pyrrolyl, quinolinyl, thiazolyl,thienopyridinyl, thienyl, triazolyl, thiadiazolyl, and triazinyl.

The term “heterocyclyl,” as used herein, refers to a five-, six-, orseven-membered ring containing one, two, or three heteroatomsindependently selected from the group consisting of nitrogen, oxygen,and sulfur. The five-membered ring has zero to two double bonds and thesix- and seven-membered rings have zero to three double bonds. The term“heterocyclyl” also includes bicyclic groups in which the heterocyclylring is fused to a phenyl group, a monocyclic cycloalkenyl group, amonocyclic cycloalkyl group, or another monocyclic heterocyclyl group.The heterocyclyl groups of the present invention can be attached to theparent molecular moiety through a carbon atom or a nitrogen atom in thegroup. Examples of heterocyclyl groups include, but are not limited to,benzothienyl, furyl, imidazolyl, indolinyl, indolyl, isothiazolyl,isoxazolyl, morpholinyl, oxazolyl, piperazinyl, piperidinyl, pyrazolyl,pyridinyl, pyrrolidinyl, pyrrolopyridinyl, pyrrolyl, thiazolyl, thienyl,and thiomorpholinyl.

The term “heterocyclylalkyl,” as used herein, refers to an alkyl groupsubstituted with one, two, or three heterocyclyl groups.

The term “heterocyclylalkylene,” as used herein, refers to a divalentheterocyclylalkyl group, where one point of attachment to the parentmolecular moiety is on the heterocyclyl portion and the other is on thealkyl portion.

The term “heterocyclylene,” as used herein, refers to a divalentheterocyclyl group.

The term “hydroxy,” as used herein, refers to —OH.

The term “imaging moiety,” as used herein, refer to a portion orportions of a molecule that allow for the detection, imaging, and/ormonitoring of the presence and/or progression of a condition(s),pathological disorder(s), and/or disease(s).

The term “linking group,” as used herein, refers to a portion of amolecule that serves as a spacer between two other portions of themolecule. Linking groups may also serve other functions as describedherein. Examples of linking groups include linear, branched, or cyclicalkyl, aryl, ether, polyhydroxy, polyether, polyamine, heterocyclic,aromatic, hydrazide, peptide, peptoid, or other physiologicallycompatible covalent linkages or combinations thereof.

As used herein, the term “lipid” refers to a synthetic ornaturally-occurring amphipathic compound which comprises a hydrophiliccomponent and a hydrophobic component. Lipids include, for example,fatty acids, neutral fats, phosphatides, glycolipids, aliphatic alcoholsand waxes, terpenes and steroids. Exemplary compositions which comprisea lipid compound include suspensions, emulsions and vesicularcompositions.

“Liposome” refers to a generally spherical cluster or aggregate ofamphipathic compounds, including lipid compounds, typically in the formof one or more concentric layers, for example, bilayers. They may alsobe referred to herein as lipid vesicles.

A “lyophilization aid” is a component that has favorable physicalproperties for lyophilization, such as the glass transition temperature,and is generally added to the formulation to improve the physicalproperties of the combination of all the components of the formulationfor lyophilization.

The term “oxo,” as used herein, refers to ═O.

As used herein, the phrase “pharmaceutically acceptable” refers to thosecompounds, materials, compositions, and/or dosage forms that are, withinthe scope of sound medical judgment, suitable for use in contact withthe tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

The term “pharmaceutically acceptable salt,” as used herein, representssalts or zwitterionic forms of the compounds of the present inventionwhich are water or oil-soluble or dispersible, which are, within thescope of sound medical judgment, suitable for use in contact with thetissues of patients without excessive toxicity, irritation, allergicresponse, or other problem or complication commensurate with areasonable benefit/risk ratio, and are effective for their intended useThe salts can be prepared during the final isolation and purification ofthe compounds or separately by reacting a suitable nitrogen atom with asuitable acid. Representative acid addition salts include acetate,adipate, alginate, citrate, aspartate, benzoate, benzenesulfonate,bisulfate, butyrate, camphorate, camphorsulfonate; digluconate,glycerophosphate, hemisulfate, heptanoate, hexanoate, formate, fumarate,hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate,lactate, maleate, mesitylenesulfonate, methanesulfonate,naphthylenesulfonate, nicotinate, 2-naphthalenesulfonate, oxalate,palmoate, pectinate, persulfate, 3-phenylproprionate, picrate, pivalate,propionate, succinate, tartrate, trichloroacetate, trifluoroacetate,phosphate, glutamate, bicarbonate, para-toluenesulfonate, andundecanoate. Examples of acids which can be employed to formpharmaceutically acceptable addition salts include inorganic acids suchas hydrochloric, hydrobromic, sulfuric, and phosphoric, and organicacids such as oxalic, maleic, succinic, and citric.

By “reagent” is meant a compound of this disclosure capable of directtransformation into a metallopharmaceutical of this disclosure. Reagentsmay be utilized directly for the preparation of themetallopharmaceuticals of this disclosure or may be a component in a kitof this disclosure.

A “reducing agent” is a compound that reacts with a radionuclide, whichis typically obtained as a relatively unreactive, high oxidation statecompound, to lower its oxidation state by transferring electron(s) tothe radionuclide, thereby making it more reactive. Reducing agentsuseful in the preparation of radiopharmaceuticals and in diagnostic kitsuseful for the preparation of said radiopharmaceuticals include, forexample, stannous chloride, stannous fluoride, formamidine sulfinicacid, ascorbic acid, cysteine, phosphines, and cuprous or ferrous salts.Other reducing agents are described, for example, in Brodack et. al.,PCT Application 94/22496.

A “stabilization aid” is a component that is typically added to themetallopharmaceutical or to the diagnostic kit either to stabilize themetallopharmaceutical or to prolong the shelf-life of the kit before itmust be used. Stabilization aids can be antioxidants, reducing agents orradical scavengers and can provide improved stability by reactingpreferentially with species that degrade other components or themetallopharmaceuticals.

By “stable compound” or “stable structure” is meant herein a compoundthat is sufficiently robust to survive isolation to a useful degree ofpurity from a reaction mixture, and formulation into an efficaciouspharmaceutical agent.

A “solubilization aid” is a component that improves the solubility ofone or more other components in the medium required for the formulation.

The term “thiol protecting group,” as used herein, refers to a groupintended to protect a thiol group against undesirable reactions duringsynthetic procedures. Any thiol protecting group known in the art may beused. Examples of thiol protecting groups include, but are not limitedto, the following: acetamidomethyl, benzamidomethyl, 1-ethoxyethyl,benzoyl, and triphenylmethyl.

A “transfer ligand” is a ligand that forms an intermediate complex witha metal ion that is stable enough to prevent unwanted side-reactions butlabile enough to be converted to a contrast agent. The formation of theintermediate complex is kinetically favored while the formation of themetallopharmaceutical is thermodynamically favored. Transfer ligandsuseful in the preparation of contrast agents and in diagnostic kitsuseful for the preparation of diagnostic radiopharmaceuticals include,for example, gluconate, glucoheptonate, mannitol, glucarate,N,N,N′,N′-ethylenediaminetetraacetic acid, pyrophosphate andmethylenediphosphonate. In general, transfer ligands are comprised ofoxygen or nitrogen donor atoms.

As used herein, the term “vesicle” refers to a spherical entity which ischaracterized by the presence of an internal void. In one embodimentvesicles are formulated from lipids, including the various lipidsdescribed herein. In any given vesicle, the lipids may be in the form ofa monolayer or bilayer, and the mono- or bilayer lipids may be used toform one of more mono- or bilayers. In the case of more than one mono-or bilayer, the mono- or bilayers are generally concentric. The lipidvesicles described herein include such entities commonly referred to asliposomes, micelles, bubbles, microbubbles, microspheres and the like.Thus, the lipids may be used to form a unilamellar vesicle (comprised ofone monolayer or bilayer), an oligolamellar vesicle (comprised of abouttwo or about three monolayers or bilayers) or a multilamellar vesicle(comprised of more than about three monolayers or bilayers). Theinternal void of the vesicles may be filled with a liquid, including,for example, an aqueous liquid, a gas, a gaseous precursor, and/or asolid or solute material, including, for example, a bioactive agent, asdesired.

As used herein, the term “vesicular composition” refers to a compositionwhich is formulate from lipids and which comprises vesicles.

The present disclosure will now be described in connection with certainembodiments which are not intended to limit its scope. On the contrary,the present disclosure covers all alternatives, modifications, andequivalents as can be included within the scope of the claims. Thus, thefollowing examples will illustrate one practice of the presentinvention, it being understood that the examples are for the purposes ofillustration of certain embodiments and are presented to provide what isbelieved to be the most useful and readily understood description of itsprocedures and conceptual aspects.

Synthesis of Fenazaquin Analog Example 1A Synthesis of4-[4-(2-Hydroxyethyl)phenyl]-4-oxo-butyric acid methyl ester

To a dry 250 mL flask under a nitrogen atmosphere was added phenethylalcohol (2.50 g, 0.02 mol), anhydrous dichloromethane (150 mL), andmethyl-4-chloro-4-oxobutyrate (6.02 g, 0.04 mol). The contents of theflask were cooled to 0° C. with an ice bath. To the solution was addedaluminum chloride (25 g, 0.2 mol) in portions being careful to avoid aviolent exotherm. The resulting yellowish mixture was stirred for 3hours. At this point the reaction was quenched with ice water. Themixture was diluted with dichloromethane and transferred to a separatoryfunnel. The organic layer was washed with a saturated solution of sodiumbicarbonate, brine and then dried over magnesium sulfate. Filtration andconcentration of the filtrate under reduced pressure provided a crudeyellow oil. The oil was suspended in anhydrous methanol (100 mL) andsodium metal was added to the mixture until a pH of 9 was obtained. Themixture was stirred for 3 hours. The volume was reduced and then dilutedwith ethyl acetate. The solution was transferred to a separatory funneland washed with aqueous 0.05 N hydrochloric acid, brine and dried overmagnesium sulfate. The solution was concentrated under reduced pressureto give a crude yellow oil with a mass of 5.88 g. Column chromatography[silica gel; eluent hexanes-ethyl acetate (3:2)] provided the desiredproduct (2.69 g, 57%). ¹H (CDCl₃) δ (ppm): 2.65 (t, 2H); 2.81 (t, 2H);3.19 (t, 2H); 3.6 (s, 3H); 3.75 (t, 2H); 7.22 (d, 2H); 7.81 (d, 2H). ¹³C(CDCl₃) δ (ppm): 27.76, 33.03, 38.66, 51.52, 62.68, 127.97, 128.99,134.47, 144.78, 173.21, 197.64.

Example 1B Synthesis of 4-[4-(2-hydroxyethyl)phenyl]butyric acid methylester

A mixture of Example 1A (2.50 g, 11 mmol), 10% Pd/C (0.25 g, 0.23 mmolof Pd metal) in anhydrous methanol (25 mL) was first degassed to removeair (two vacuum/H₂ cycles) after which it was capped and a balloonfilled with H₂ was applied to it for 12 hours. After this time thereaction mixture was filtered through diatomaceous earth (Celite®) andthe filtrate was concentrated under reduced pressure to give 2.32 g ofcrude material. Column chromatography [silica gel; eluent hexanes-ethylacetate (2:1)] provided the desired product (0.92 g, 39%). ¹H (CDCl₃) δ(ppm): 1.91-1.96 (m, 2H); 2.32 (t, 2H); 2.62 (t, 2H); 2.83 (t, 2H); 3.66(s, 3H); 3.85 (t, 2H); 7.11-7.15 (m, 4H).

Example 1C Synthesis of 4-{4-[2-(quinazolin-4-yloxy)ethyl]phenyl}butyricacid methyl ester

A dry 50 mL flask was fitted with an addition funnel. To the flask wereadded 4-chloroquinazoline (592 mg, 3.6 mmol), anhydrous tetrahydrofuran(10 mL), and 60 wt % sodium hydride (187 mg, 4.7 mmol). A solution ofExample 1B (800 mg, 3.6 mmol) in anhydrous tetrahydrofuran (10 mL) wasadded dropwise using the addition funnel. The reaction was stirred for3.5 hours. The reaction was diluted with ethyl acetate and quenched bythe addition of aqueous 0.1 N hydrochloric acid. The mixture wastransferred to a separatory funnel and washed with brine. The organiclayer was dried over magnesium sulfate, filtered, and concentrated.Column chromatography [silica gel; eluent hexanes-ethyl acetate (4:1)]provided the desired product (538 mg, 43%). ¹H(CDCl₃) δ (ppm): 1.92-1.98(m, 2H); 2.33 (t, 2H); 2.64 (t, 2H); 3.19 (t, 2H); 3.66 (s, 3H); 4.79(t, 2H); 7.15 (d, 2H); 7.27 (d, 2H); 7.57 (t, 1H); 7.83 (t, 1H); 7.94(d, 1H); 8.15 (d, 1H); 8.80 (s, 1H). 26.68, 33.59, 34.93, 35.03, 51.67,67.89, 116.48, 123.72, 127.23, 127.82, 128.87, 129.24, 133.74, 135.76,139.90, 151.08, 154.56, 166.89, 174.10.

Example 1D Synthesis of4-{4-[2-(Quinazolin-4-yloxy)ethyl]phenyl}butan-1-ol

To a dry 15 mL flask was added lithium aluminum hydride (233 mg, 6.0mmol) and anhydrous diethyl ether (3 mL). The mixture was cooled with anice bath. A solution of Example 1C (538 mg, 1.54 mmol) in anhydrousdiethyl ether (3 mL) was slowly added with vigorous stirring. The bathwas removed and the slurry was stirred for 15 minutes. The reaction wasquenched with water (0.233 mL), aqueous 15% sodium hydroxide (0.233 mL)and water (0.699 mL). The white solid was filtered and the filtrate wasdried over magnesium sulfate, filtered, and concentrated under reducedpressure to give a clear oil. The oil was then dissolved in anhydrousdichloromethane (10 mL) and manganese(IV) oxide (500 mg, 5.8 mmol) wasadded to the solution. The mixture was stirred for 12 hours. Filtrationthrough diatomaceous earth (Celite®) followed by concentration of thefiltrate under reduced pressure afforded 395 mg of crude product. Columnchromatography [silica gel; eluent pentane-ethyl acetate (2:3)] providedthe desired product (225 mg, 49%). ¹H (CDCl₃) δ (ppm): 1.55-1.61 (m,2H); 1.65-1.68 (m, 2H); 2.61 (t, 2H); 3.17 (t, 2H); 3.64 (t, 2H); 4.79(t, 2H); 7.12 (d, 2H); 7.23 (d, 2H); 7.56 (t, 1H); 7.82 (t, 1H); 7.93(d, 1H); 8.14 (d, 1H); 8.77 (s, 1H). ¹³C (CDCl₃) δ (ppm): 27.52, 32.31,34.89, 35.21, 62.81, 67.74, 116.67, 123.54, 127.08, 127.49, 128.63,128.98, 133.61, 135.23, 140.64, 150.68, 154.29, 166.79.

Example 1E Synthesis of Toluene-4-sulfonic acid4-{4-[2-(quinazolin-4-yloxyethyl]phenyl}butyl ester

To a dry 10 mL flask was added p-toluenesulfonyl chloride (32.5 mg, 0.17mmol), 4-(dimethylamino)pyridine (20.7 mg, 0.17 mmol), Example 1D (50.0mg, 0.16 mmol), anhydrous dichloromethane (1 mL) and triethylamine (17.2mg, 0.17 mmol). The resulting solution was stirred for 2 hours,concentrated under reduced pressure, and purified by columnchromatography [silica gel; eluent pentane-ethyl acetate (1.86:1)] toprovide the desired product (52 mg, 70%). ¹H(CDCl₃) δ (ppm): 1.64-1.68(m, 4H); 2.44 (s, 3H); 2.56 (t, 2H); 3.19 (t, 2H); 4.04 (t, 2H); 4.78(t, 2H); 7.08 (d, 2H); 7.26 (d, 2H); 7.57 (t, 1H); 7.78 (d, 2H); 7.84(t, 1H), 8.14 (d, 1H); 8.80 (s, 1H).

Example 1F Synthesis of 4-{2-[4-(4-Fluorobutyl)phenyl]ethoxy}quinazoline

A dry 5 mL flask was fitted with a reflux condenser. To the flask wasadded potassium fluoride (6.1 mg, 0.1 mmol), kryptofix (40 mg, 0.1 mmol)and anhydrous acetonitrile (0.5 mL) To the resulting solution was addeda solution of Example 1E (25 mg, 0.05 mmol) in anhydrous acetonitrile (1mL) The flask was placed in a 90° C. oil bath. The solution was stirredfor 1 hour. After cooling the reaction mixture was diluted with diethylether, transferred to a separatory funnel, and washed with aqueous 0.1 Nhydrochloric acid, saturated aqueous solution of sodium bicarbonate, andthen brine. The organic layer was dried with magnesium sulfate,filtered, and concentrated under reduced pressure. Column chromatography[silica gel; eluent hexanes-ethyl acetate (3:1)] provided the desiredproduct (10.7 mg, 63%). ¹H(CDCl₃) δ (ppm): 1.65-1.73 (m, 4H); 2.63 (t,2H); 3.17 (t, 2H); 4.40 (t, 1H); 4.48 (t, 1H); 4.77 (t, 2H); 7.13 (d,2H); 7.24 (d, 2H); 7.55 (1H); 7.82 (t, 1H); 7.92 (d, 1H); 8.13 (d, 1H);8.78 (s, 1H). ¹³C (CDCl₃) δ (ppm): 27.19 (d, ⁴J_(CF)=4.5), 30.20 (d,³J_(CF)=19.5), 35.15 (d, ²J_(CF)=27.0), 67.94, 84.17 (d, ¹J_(CF)=163.3),116.93, 123.75, 127.26, 127.84, 128.82, 129.23, 129.42, 133.77, 135.62,138.21, 140.54, 151.08, 154.59. ¹⁹F(CDCl₃, CFCl₃ internal standard) δ(ppm): −218.59 (t of t, J=−27.6, −50.4).

Synthesis of Pyridaben Analogs Example 2A Synthesis of Butyric acid4-phenylbutyl ester

To 4-phenyl-1-butanol (7.0 g, 0.047 mol) was added anhydrousdichloromethane (20 mL). A solution of butyryl chloride (4.79 g, 0.045mol) in anhydrous dichloromethane (20 mL) was added dropwise. Thesolution was stirred for 36 hours. At this point the reaction wasconcentrated under reduced pressure to give a crude oil. Columnchromatography [silica gel; eluent hexanes-ethyl acetate (3:1)] providedthe desired product (9.8 g, 94%) as a clear viscous liquid. ¹H(CDCl₃) δ(ppm): 0.94 (t, 3H); 1.61-1.71 (m, 6H); 2.27 (t, 2H); 2.64 (t, 2H); 4.08(t, 2H); 7.16-7.19 (m, 3H); 7.25-7.29 (m, 2H).

Example 2B Synthesis of 4-(4-Hydroxybutyl)benzoic acid methyl ester

To aluminum chloride (6.7 g, 0.05 mol) in a dry 250 mL round bottomflask was added anhydrous dichloromethane (100 mL). The flask was cooledin a 0° C. ice bath. Oxalyl chloride (6.4 g, 0.05 mol) was addeddropwise to the flask. The mixture was allowed to stir for 5 minutes. Asolution of Example 2A (9.8 g, 0.044 mol) in anhydrous dichloromethane(50 mL) was then added dropwise. The mixture was allowed to stir for 4hours at 0° C. The reaction mixture was poured into a reparatory funnelcontaining ice and brine. The organic layer was washed with brine anddried over magnesium sulfate. Filtration and concentration under reducedpressure provided 9.1 g of yellow oil. 9.0 g of this oil was suspendedin methanol and the pH adjusted to 2 and stirred for 48 hours. Thereaction mixture was concentrated under reduced pressure. Columnchromatography [silica gel; eluent hexanes-ethyl acetate (2.57:1)]provided the desired product (2.80 g, 31%) as a clear viscous liquid. ¹H(CDCl₃) δ (ppm): 1.56-1.61 (m, 2H); 1.63-1.73 (m, 2H); 2.67 (t, 2H);3.64 (t, 2H); 3.88 (s, 3H); 7.23 (d, 2H); 7.93 (d, 2H).

Example 2C Synthesis of 4-[4-(tert-Butyldimethylsilanyloxy)butyl]benzoicacid methyl ester

To Example 2B (1.0 g, 4.8 mmol) was added anhydrous dimethylformamide(10 mL), imidazole (0.5 g, 7.2 mmol) and tert-butyldimethylsilylchloride (1.08 g, 7.3 mmol). The solution was stirred in a water bathfor 2 hours. The reaction mixture was diluted with ethyl acetate, pouredinto a separatory funnel, washed with water (20 mL, 5×) then washed witha saturated sodium bicarbonate solution (20 mL, 2×). The organic layerwas dried with magnesium sulfate, filtered, and concentrated underreduced pressure to give the desired product (1.17 g, 75%) which wasused without further purification in the next step.

Example 2D Synthesis of{4-[4-(tert-Butyldimethylsilanyloxy)butyl]phenyl}-methanol

To Example 2C (1.17 g, 3.6 mmol) was added anhydrous diethyl ether (14mL). The solution was cooled to 0° C. with an ice bath. Lithium aluminumhydride (0.28 g, 7.2 mmol) was added to the solution in portions. Themixture was stirred for 1 hour. To the reaction mixture was addeddistilled water (0.28 mL) and the mixture was stirred for 5 minutes.Next was added an aqueous 15% sodium hydroxide solution and the mixturewas stirred for 5 minutes. Lastly distilled water (0.84 mL) was addedand the mixture was stirred for 5 minutes. The white solid was removedby filtration. The filtrate was dried with magnesium sulfate, filtered,and concentrated to give 1.23 g of crude product. Column chromatography[silica gel; eluent hexanes-ethyl acetate (4:1)] provided the desiredproduct (1.02 g, 96%) as a clear viscous liquid.

Example 2E Synthesis of2-tert-Butyl-5-{4-[4-(tert-butyldimethylsilanyloxy)butyl]benzyloxy}-4-chloro-2H-pyridazin-3-one

To a dry 25 mL round bottom flask, fitted with a reflux condenser, wasadded the product of Example 2D (0.41 g, 1.4 mmol),2-tert-butyl-4,5-dichloro-2H-pyridazin-3-one (0.93 g, 4.2 mmol), cesiumcarbonate (1.37 g, 4.2 mmol), and anhydrous dimethylformamide (11 mL).The reaction flask was placed in a 68° C. oil bath and the reaction wasstirred for 12 hours. The reaction flask was removed from the oil bathand allowed to cool. The mixture was diluted with ethyl acetate,transferred to a separatory funnel and washed with water (25 mL, 5×).The organic layer was dried with magnesium sulfate, filtered, andconcentrated under reduced pressure to give 1.3 g of crude product.Column chromatography [silica gel; eluent hexanes-ethyl acetate (9:1)]provided the desired product (594 mg, 89%). ¹H(CDCl₃) δ (ppm): 0.05 (s,6H); 0.90 (s, 9H); 1.64 (s, 9H); 2.65 (t, 2H); 3.64 (t, 2H); 5.23 (s,2H); 7.23 (d, 2H); 7.33 (d, 2H); 7.74 (s, 1H). ¹³C (CDCl₃) δ (ppm):18.57, 26.19, 27.75, 28.09, 32.58, 35.61, 63.14, 66.57, 72.14, 118.46,125.41, 127.44, 129.23, 132.38, 143.72, 154.02, 159.30.

Example 2F Synthesis of2-tert-Butyl-4-chloro-5-[4-(4-hydroxy-butyl)-benzyloxy]-2H-pyridazin-3-one

To the product of Example 2E (594 mg, 1.45 mmol) was added anhydroustetrahydrofuran (3 mL) and a 1.0 M solution of tert-butylammoniumfluoride in tetrahydrofuran (2.9 mL, 2.9 mmol). The solution was stirredfor 1 hour then concentrated under reduced pressure. Columnchromatography [silica gel; eluent pentane-ethyl acetate (1.8:1)]provided the desired product (410 mg, 77%). ¹H (CDCl₃) δ (ppm):1.61-1.64 (m, 11H); 1.67-1.74 (m, 2H); 2.68 (t, 2H); 3.68 (t, 2H); 5.23(s, 2H); 7.23 (d, 2H); 7.33 (d, 2H); 7.74 (s, 1H). ¹³C (CDCl₃) δ (ppm):27.43, 27.86, 32.56, 35.35, 62.74, 66.36, 71.88, 118.27, 125.18, 127.27,128.99, 132.28, 143.17, 153.78, 159.07.

Example 2G Synthesis of Toluene-4-sulfonic acid4-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)-phenyl]-butylester

To a 5 mL round bottom flask was added the product of Example 2F (200mg, 0.55 mmol), p-toluenesulfonyl chloride (125 mg, 0.66 mmol),4-(dimethylamino)pyridine (80 mg, 0.66 mmol), diisopropylethylamine (85mg, 0.66 mmol) and anhydrous dichloromethane (2 mL). The resultingsolution was stirred for 2 hours. The reaction mixture was diluted withethyl acetate, transferred to a separatory funnel and washed with asolution of aqueous 0.1 N hydrochloric acid and then washed with brine.The organic layer was dried with magnesium sulfate, filtered, andconcentrated under reduced pressure to give 299 mg of crude product.Column chromatography [silica gel; eluent pentane-ethyl acetate (3:1)]provided the desired product (197 mg, 69%). ¹H(CDCl₃) δ (ppm): 1.62-1.70(m, 13H); 2.43 (s, 3H); 2.58 (t, 2H); 4.03 (t, 2H); 7.15 (d, 2H);7.29-7.33 (m, 4H); 7.72 (s, 1H); 7.77 (d, 2H). ¹³C (CDCl₃) δ (ppm):21.63, 26.98, 27.86, 28.34, 34.80, 66.37, 70.23, 71.81, 118.25, 125.12,127.32, 127.87, 128.93, 129.82, 132.48, 133.15, 142.40, 144.72, 153.75,159.05.

Example 2H Synthesis of2-tert-butyl-4-chloro-5-(4-(4-fluorobutyl)benzyl)oxy 3(2H)pyridazinone

The product of Example 2G (57 mg, 0.10 mmol) was dissolved in 1 mLacetonitrile and to this was added a mixture of KF-K222 (1:1; 0.164mmol) dissolved in 1 mL acetonitrile. The entire mixture was thenimmersed in an oil bath at 90° C. and heated at reflux for 15 minutes atwhich point the reaction was shown to be complete by TLC. The volatilecomponents were removed in vacuo and the crude oil was purified by flashsilica gel chromatography (hexanes-ethyl acetate (4:1)) to provide 28 mgof the desired product as a oil which solidified upon standing. ¹H(CDCl₃) δ (ppm): 1.6 (s, 9H), 1.7 (m, 4H), 2.6 (t, 2H), 4.44 (d oft, 2H,J=47.4 & 6 Hz), 5.2 (s, 2H), 7.2 (d, 2H, J=8.4 Hz), 7.3 (d, 2H, J=8.4Hz), 7.71 (s, 1H). ¹³C (CDCl₃) δ (ppm): 26.8 (³J_(CF)=4.65 Hz), 27.8,29.8 (²J_(CF)=19.8 Hz), 35.1, 66.3, 71.8, 83.8 (¹J_(CF)=163.8 Hz),118.2, 125.1, 127.2, 128.9, 132.3, 142.8, 153, 159. ¹⁹F(CDCl₃, CFCl₃ asinternal standard) δ (ppm): −218.6 (t of t, J=−27.6, −50.4)

Example 3A Synthesis of (±)-1-tert-butyldimethylsilyloxy-2-hydroxybutane

A 50 mL round bottom flask was charged with (±)-1,2-butanediol (1 g,11.09 mmol) and to it was added dimethylformamide (8 mL) followed bytert-butyldimethylsilyl chloride (2.5 g, 16.64 mmol) and imidazole (1.88g, 27.7 mmol). The reaction mixture was stirred for 10 hours after whichit was diluted with dichloromethane and poured into a separatory funneland washed with water (80 mL) and brine and dried over magnesiumsulfate. After filtration and concentration the crude oil was purifiedby silica gel flash chromatography (hexanes:ethylacetate) to obtain 1 gmof pure desired product in 45% yield. ¹H (CDCl₃) δ (ppm): 3.6 (m, 1H).3.5 (m, 1H), 3.4 (m, 1H), 2.4 (s, 1H), 1.44 (m, 2H), 0.99 (t, 3H), 0.9(s, 9H), 0.06 (s, 6H).

Example 3B Synthesis of (±)-4-(1-tertbutyldimethylsilyloxybut-2-oxy)methylbenzoate

4-Hydroxymethylbenzoate (1.1 g, 7.34 mmol), the product of Example 3A(0.75 g, 3.67 mmol) and triphenylphosphine (1.972 g, 7.34 mmol) wereadded to a round bottom flask and 8 mL tetrahydrofuran was added. Theflask was cooled in an ice bath to 0° C. after whichdiisopropylazodicarboxylate (1.485 g, 7.34 mmol) was added via syringe.The reaction mixture was stirred for 2 hours after which the reactionwas deemed complete by thin layer chromatography. All the solvent wasremoved under reduced pressure and the crude oil directly subjected topurification by silica gel flash chromatography (hexanes:diethyl ether)to obtain 1.0 gm (83%) of the desired compound as a thick oil. ¹H(CDCl₃) δ (ppm): 7.9 (d, 2H), 6.9 (d, 2H), 4.3 (p, 1H, J=5.4 Hz), 3.9(s, 3H), 3.7 (2H), 1.78 (m, 1H), 1.7 (m, 1H), 0.9 (t, 3H, J=7.8 Hz),0.89 (s, 9H), 0.05 (s, 3H), 0.01 (s, 3H). ¹³C (CDCl₃) δ (ppm): 166.8,162.8, 131.5, 122.3, 115.2, 80, 64.5, 51.7, 25.8, 24.1, 18.2, 9.5, −5.3.

Example 3C Synthesis of (±)-4-(1-tertbutyldimethylsilyloxybut-2-oxy)benzylalcohol

To a solution of the product of Example 3B (1 g, 2.95 mmol) in ether (15mL) was added lithium aluminum hydride (0.336 g, 8.8 mmol) and themixture was stirred under nitrogen for 1.5 hours. The reaction wascomplete as shown by TLC by this time and was quenched by addition of0.336 mL water, 0.336 mL of 15% NaOH solution and 1.00 mL water insuccession. The resulting mixture was stirred for an additional 20minutes after which the white precipitate formed was filtered and washedwith ether. The filtrate was then dried over magnesium sulfate.Filtration and removal of the solvent gave 0.50 g (54%) of the desiredproduct as a white solid. ¹H (CDCl₃) δ (ppm): 7.2 (d, 2H), 6.9 (d, 2H),4.3 (p, 1H), 3.77 (d of d, 1H), 3.66 (d of d, 1H), 1.77-1.72 (m, 1H),1.68-1.61 (m, 1H), 1.5 (t, 1H, J=5.4 Hz), 0.9 (t, 3H, J=7.8 Hz), 0.89(s, 9H), 0.04 (s, 3H), 0.01 (s, 3H). ¹³C (CDCl₃) δ (ppm): 158.5, 133,128.4, 116.1, 80.1, 65, 64.5, 25.8, 24.1, 18.2, 9.5, −5.3

Example 3D Synthesis of (±)-2-tert-butyl 4-chloro5-(4-(1-tertbutyldimethylsilyloxy but-2-oxy)benzyl)oxy3(2H)-pyridazinone

(±)-2-Tert-butyl-4-chloro-5-hydroxy-3(2H)-pyridazinone (0.48 g, 2.417mmol) was charged to a 100 mL round bottom flask and tetrahydrofuran (40mL) was added. After the solution turned clear, Example 3C (0.5 g, 1.611mmol) and triphenylphosphine (0.633 g, 2.417 mmol) were added to theflask and the flask was cooled to 0° C. Diisopropyl azodicarboxylate(0.488 g, 2.417 mmol, 0.468 mL) was then added via a syringe and thereaction was stirred for two hours after which time it was shown to becomplete by TLC. The contents of the flask were then concentrated invacuo and the crude oil obtained was purified by flash chromatographyusing silica gel (hexanes:ethyl acetate) to obtain 0.33 g of the desiredcompound as an oil. ¹H (CDCl₃) δ (ppm): 7.72 (s, 1H), 7.2 (d, 2H), 6.9(d, 2H), 5.2 (s, 2H), 4.2 (p, 1H), 3.75 (d of d, 1H), 3.68 (d of d, 1H),1.75 (m, 2H), 1.65 (m, 1H), 1.6 (s, 9H), 0.99 (t, 3H), 0.85 (s, 9H),0.04 (s, 3H), 0.02 (s, 3H). ¹³C (CDCl₃) δ (ppm): 159.6, 159.3, 154, 129,126.9, 125, 118.5, 116.5, 80.3, 72.1, 66.5, 64.8, 28.1, 26, 24.4, 18.4,9.6, −5.3

Example 3E Synthesis of(±)-2-tert-butyl-4-chloro-5-(4-(1-hydroxy-but-2-oxy)benzyl)oxy-3(2H)-pyridazinone

To the product of Example 3D (0.3 g, 0.6 mmol) in a 10 mL round bottomflask was added tetrahydrofuran (2 mL). Upon solution,tetrabutylammonium fluoride (1.8 mmol, 1.8 mL, 1M solution in THF) wasadded and the reaction mixture was stirred for 90 minutes. The contentswere then concentrated under reduced pressure and the crude mixturepurified by flash chromatography using silica gel (hexanes:ethylacetate) to obtain 185 mg (80%) of pure desired product. ¹H (CDCl₃) δ(ppm): 7.74 (s, 1H), 7.3 (d, 2H), 6.9 (d, 2H), 5.2 (s, 2H), 4.3 (m, 1H),3.81-3.77 (two br s, 2H), 1.84 (br t, 1H), 1.77-1.69 (m, 2H), 1.64 (s,9H), 0.98 (t, 3H); ¹³C (CDCl₃) δ (ppm): 159.2, 158.9, 153.9, 129.2,127.5, 125.4, 116.6, 80.4, 71.9, 66.5, 64.2, 28, 23.5, 9.7.

Example 3F Synthesis of (±)-2-tert-butyl 4-chloro5-(4-(1-tosyloxy-but-2-oxy)benzyl)oxy 3(2H)-pyridazinone

Into a 10 mL round bottom flask was added the product of Example 3E(0.05 g, 0.13 mmol) followed by dichloromethane (2 mL). Toluenesulfonylchloride (0.075 g, 0.39 mmol), 4-N,N-dimethylaminopyridine (0.048 g,0.39 mmol) and diisopropylethylamine (0.05 g, 0.39 mmol, 68.7 μl) werethen added in succession to the reaction mixture and this was stirredfor 35 minutes. Water was then added to the mixture and the solutionpoured into a separatory funnel and the layers separated. The organiclayer was washed with water and brine and dried over magnesium sulfate.The crude oil obtained after filtration and concentration was purifiedby silica gel flash chromatography (hexanes:ethyl acetate) to obtain 54mg (77%) of the desired compound as a thick colorless oil. ¹H (CDCl₃) δ(ppm): 7.74 (3H, two singlets), 7.3 (m, 4H), 6.8 (d, 2H), 5.2 (s, 2H),4.38 (p, 1H), 4.15 (m, 2H), 2.44 (s, 3H), 1.72 (m, 2H), 1.6 (s, 9H),0.95 (t, 3H); ¹³C (CDCl₃) δ (ppm): 159.2, 158.5, 153.9, 145.1, 133, 130,129, 128.1, 127.2, 125.4, 118.5, 116.5, 71.9, 70.2, 66.6, 28.1, 24.2,21.8, 9.4.

Example 3G Synthesis of (±)-2-tert-butyl-4-chloro5-(4-(1-fluoro-but-2-oxy)benzyl)oxy-3(2H)-pyridazinone

The product of Example 3F (28 mg, 52.4 mop was dissolved in 0.5 mLacetonitrile in a 5 mL flask and to this was added a solution ofpotassium fluoride (4.5 mg, 78.6 μmol) and Kryptofix 222 (29.6 mg, 78.6μmol) in 0.5 mL acetonitrile. The above solution was then immersed in aoil bath preheated to 90° C. The reaction was allowed to stir for 90minutes after which all the volatiles were removed under reducedpressure and the crude mixture purified by preparative thin layerchromatography to obtain 13 mg (65%) of pure desired compound. ¹H(CDCl₃) δ (ppm): 7.72 (s, 1H), 7.3 (d, 2H), 6.9 (d, 2H), 5.23 (s, 2H),4.57-4.59 (m, 2H), 4.4 (m, 4H), 1.74 (m, 2H), 1.6 (s, 9H), 1.0 (t, 3H).¹³C (CDCl₃) δ (ppm): 159, 158.7, 153.7, 129, 127.5, 125.2, 118.3, 116.4,83.85 (d, ¹J_(CF)=172.2), 78, 71.1, 66.3, 27.8, 23.2, 9.48. ¹⁹F (CDCl₃,CFCl₃ as internal standard) δ (ppm): −228 (d of t, J=−19, −60 Hz)

Example 4A Synthesis of 4-(3-hydroxypropoxy)-benzoic acid methyl ester

To a 250 mL flask was added 3-bromo-1-propanol (4.17 g, 0.03 mol),anhydrous dimethylformamide (40 mL), methyl-4-hydroxybenzoate (3.0 g,0.02 mol) and potassium carbonate (4.15 g, 0.03 mol). The flask wasplaced in a 50° C. oil bath and stirred for 12 hours. After cooling thereaction was diluted with ethyl acetate, transferred to separatoryfunnel, washed with aqueous 0.1 N hydrochloric acid, water then brine.The organic layer was dried with magnesium sulfate, filtered, andconcentrated under reduced pressure to give 5.14 g of crude oil. Columnchromatography [silica gel; eluent hexanes-ethyl acetate (1.68:1)]provided the desired product (1.25 g, 30%) as a white powder. ¹H (CDCl₃)δ (ppm): 2.04-2.08 (m, 2H); 3.86-3.88 (m, 5H); 4.17 (t, 2H); 6.91 (d,2H); 7.98 (d, 2H); ¹³C (CDCl₃) δ (ppm): 31.89, 51.81, 59.88, 65.50,114.06, 122.67, 131.57, 162.60, 166.84.

Example 4B Synthesis of4-[3-(tert-Butyldimethylsilanyloxy)propoxy]benzoic acid methyl ester

To a 50 mL flask was added Example 4A (300 mg, 1.4 mmol), anhydrousdimethylformamide (4 mL), tert-butyldimethylsilyl chloride (317 mg, 2.1mmol), and imidazole (146 mg, 2.1 mmol). The resulting solution wasstirred for 2 hours. At this point the reaction was diluted with ethylacetate and transferred to a separatory funnel. The organic phase waswashed with aqueous 0.1 N hydrochloric acid (2×), water (2×), thenbrine. The organic layer was then dried over magnesium sulfate,filtered, and concentrated. Column chromatography [silica gel; eluenthexanes-ethyl acetate (9.5:1)] provided the desired product (413 mg,91%). ¹H (CDCl₃) δ (ppm): 0.03 (s, 6H); 0.87 (s, 9H); 1.97-2.01 (m, 2H);3.79 (t, 2H); 3.87 (s, 3H); 4.11 (t, 2H); 6.90 (d, 2H); 7.97 (d, 2H);¹³C (CDCl₃) δ (ppm): 18.30, 25.89, 32.3, 51.78, 59.27, 64.67, 114.08,122.43, 131.56, 162.90, 166.90

Example 4C Synthesis of{4-[3-(tert-Butyldimethylsilanyloxy)propoxy]phenyl}methanol

Example 4B (396 mg, 1.22 mmol) was added to a dry 50 mL flask along withanhydrous diethyl ether (10 mL) The flask was lowered into an ice bath.Lithium aluminum hydride (93 mg, 2.44 mmol) was added in portions to thereaction flask. The mixture was allowed to stir in the bath for 2 hours.The reaction was quenched with water (0.093 mL), aqueous 15% sodiumhydroxide (0.093 mL) then water (0.279 mL). The white solid was filteredoff and the filtrate was dried over magnesium sulfate, filtered, andconcentrated to give the desired product (291 mg, 80%). ¹H(CDCl₃) δ(ppm): 0.04 (s, 6H); 0.88 (s, 9H); 1.95-1.99 (m, 2H); 3.79 (t, 2H); 4.05(t, 2H); 4.60 (s, 2H); 6.88-6.89 (m, 2H); 7.25-7.27 (m, 2H); (CDCl₃) δ(ppm): 18.30, 25.91, 32.41, 59.50, 64.57, 65.10, 114.59, 128.60, 132.97,158.75.

Example 4D Synthesis of2-tert-butyl-4-chloro-5-{4-[3-(tert-butyldimethylsilanyloxy)propoxy]benzyloxy}-2H-pyridazin-3-one

To a dry 25 mL flask was added Example 4C (211 mg, 0.71 mmol) andanhydrous tetrahydrofuran (3 mL). The flask was cooled in an ice bath.To the flask was added triphenylphosphine (187 mg, 0.71 mmol) and2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (142 mg, 0.71 mmol).Lastly, diisopropyl azodicarboxylate (144 mg, 0.71 mmol) was added. Thereaction mixture was allowed to stir in the ice bath for 1 hour. At thispoint the mixture was diluted with diethyl ether and transferred to aseparatory funnel. The organic solution was washed with water and thenbrine, dried over magnesium sulfate, filtered, and concentrated underreduced pressure. Column chromatography [silica gel; eluenthexanes-ethyl acetate (9:1)] provided the desired product (106 mg, 31%).¹H (CDCl₃) δ (ppm): 0.03 (s, 6H); 0.87 (s, 9H); 1.62 (s, 9H); 1.95-1.99(m, 2H); 3.79 (t, 2H); 4.06 (t, 2H); 5.23 (s, 2H); 6.91-6.92 (m, 2H);7.30-7.31 (m, 2H); 7.72 (s, 1H); ¹³C (CDCl₃) δ (ppm): 18.29, 25.90,27.87, 32.34, 59.41, 64.63, 66.30, 71.89, 114.90, 118.34, 125.34,126.68, 128.92, 153.79, 159.07, 159.55

Example 4E Synthesis of2-tert-butyl-4-chloro-5-[4-(3-hydroxypropoxy)-benzyloxy]-2H-pyridazin-3-one

To a dry 10 mL flask was added Example 4D (100 mg, 0.21 mmol) along withanhydrous tetrahydrofuran (2 mL) To the flask was added a solution of1.0 M tetrabutylammonium fluoride in tetrahydrofuran (0.42 mL, 0.42mmol). The solution was stirred for 2 hours. At this point the reactionwas concentrated under reduced pressure. Preparatory thin layerchromatography [silica gel; eluent hexanes-ethyl acetate (1:1)] providedthe desired product (57.8 mg, 76%). ¹H (CDCl₃) δ (ppm): 1.62 (s, 9H);2.02-2.06 (m, 2H); 3.86 (t, 2H); 4.13 (t, 2H); 5.30 (s, 2H); 6.92-6.93(m, 2H); 7.31-7.32 (m, 2H); 7.71 (s, 1H); ¹³C (CDCl₃) δ (ppm): 27.87,31.97, 60.24, 65.67, 66.34, 71.81, 114.91, 118.37, 125.31, 127.06,128.98, 153.76, 159.07, 159.27.

Example 4F Synthesis of toluene-4-sulfonic acid3-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)phenoxy]propylester

To a dry 5 mL flask was added Example 4E (40 mg, 0.11 mmol),4-methyl-benzenesulfonyl chloride (31 mg, 0.16 mmol),4-(dimethylamino)pyridine (20 mg, 0.16 mmol), diisopropylethylamine(16.6 mg, 0.16 mmol) and anhydrous dichloromethane (0.6 mL). Theresulting solution was stirred for 1 hour. The reaction mixture wasconcentrated under reduced pressure. Preparatory thin layerchromatography [silica gel; eluent pentane-ethyl acetate (3:2)] providedthe desired product (18.6 mg, 33%). ¹H (CDCl₃) δ (ppm): 1.62 (s, 9H);2.09-2.13 (m, 2H); 2.37 (s, 3H); 3.95 (t, 2H); 4.23 (t, 2H); 5.22 (s,2H); 6.78 (d, 2H); 7.23 (d, 2H); 7.29 (d, 2H); 7.73-7.75 (m, 3H). ¹³C(CDCl₃) δ (ppm): 21.60, 27.85, 28.81, 63.15, 66.35, 66.87, 71.75,114.76, 118.27, 125.18, 127.11, 127.83, 128.94, 129.80, 132.79, 144.80,163.72, 158.90, 159.03.

Example 4G Synthesis of2-tert-butyl-4-chloro-5-[4-(3-fluoropropoxy)benzyloxy]-2H-pyridazin-3-one

To a scintillation vial containing a suspension of Example 4F (4.5 mg,8.64×10⁻³ mmol) in anhydrous acetonitrile (0.25 mL) was added a solutionof potassium fluoride (1.6 mg, 4.07×10⁻² mmol) and kryptofix (15.0 mg,4.07×10⁻² mmol) in anhydrous acetonitrile (0.25 mL). The vial was cappedand lowered into a 90° C. oil bath. The reaction was allowed to stir for40 minutes. The reaction was cooled and concentrated under reducedpressure. Preparatory thin layer chromatography [silica gel; eluentpentane-ethyl acetate (3:2)] provided the desired product (0.8 mg, 25%).¹H(CDCl₃) δ (ppm): 1.62 (s, 9H); 2.14-2.20 (m, 2H); 4.09-4.11 (m, 2H);4.60 (t, 1H); 4.68 (t, 1H); 5.24 (s, 2H); 6.92 (d, 2H); 7.32 (d, 2H);7.72 (s, 1H); ¹⁹F(CDCl₃, CFCl₃ as internal standard) δ (ppm): −222.66 (tof t, J=28.2, −50.4)

Example 5A Synthesis of 4-(2-hydroxyethoxymethyl)benzoic acid methylester

To a two-neck round bottom flask, which was equipped with a Dewarcondenser, a solution of 4-hydroxymethylbenzoic acid methyl ester (2.50g, 0.015 mol) in anhydrous dichloromethane (30 mL) was cooled to −10° C.in a salt/ice bath. Ethylene oxide (1.10 mL) was added to the cooledstirring solution dropwise followed by the addition of boron trifluorideetherate (0.51 ml). The reaction mixture was stirred for 45 minutes andthen warmed to room temperature for 30 minutes to boil off any excess ofethylene oxide in the reaction mixture. The reaction mixture was thendiluted with brine. The aqueous layer was extracted with dichloromethane(3 times). All of the organic layers were combined, dried over Na₂SO₄,filtered, and concentrated to provide an oil. The crude material waspurified using silica gel chromatography (4:1 pentane:ethyl acetate) toprovide the desired product (537 mg, 2.56 mmol) in 17% yield. ¹H(CDCl₃8.36, 600 MHz): δ (2H, d, J=8.4 Hz), 7.41 (2H, d, J=8.5 Hz), 4.62(3H, s), 3.92 (2H, s), 3.78 (m, 2H), 3.63 (2H, m); ¹³C (CDCl₃167.1,143.5, 130.0, 129.8, 127.5, 72.9, 72.0, 150 MHz): δ 62.1, 52.3.

Example 5B Synthesis of4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]benzoic acid methylester

To a solution of the product of Example 5A (544.5 mg, 2.59 mmol) inanhydrous DMF (26 mL) was added imidazole (264 mg, 3.89 mmol) andTBDMS-Cl (586 mg, 3.89 mmol). The reaction mixture stirred at roomtemperature overnight and was quenched with water. The aqueous layer wasextracted with ethyl acetate (3×). All combined organic layers weredried over Na₂SO₄, filtered, and concentrated. The crude material waspurified using silica gel chromatography (4:1 pentane:ethyl acetate) toprovide the desired product (677.5 mg, 2.19 mmol) in 84% yield. ¹H(CDCl₃8.01, 600 MHz): δ (2H, d, J=8.3 Hz), 7.42 (2H, d, J=8.4 Hz), 4.63(2H, s), 3.91 (2H, s), 3.82 (2H, t, J=5.0), 3.58 (2H, t, J=5.1 Hz), 0.91(9H, s), 0.07 (6H, s); ¹³C (CDCl₃166.5, 143.5, 129.2, 128.8, 126.5,72.1, 71.6, 150 MHz): δ 62.3, 51.5, 25.4, 17.9, −5.8.

Example 5C Synthesis of{4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]phenyl}methanol

To a solution of the product of Example 5B (670 mg, 2.18 mmol) dissolvedin anhydrous THF (22 mL) was added a solution of LAH (1.0 M solution inTHF, 2.18 mL, 2.18 mmol) dropwise. After completion of addition thereaction mixture was stirred at room temperature for 3 hours. Thereaction mixture was diluted with water. The aqueous layer was extractedwith ethyl acetate (3×). All combined organic layers were dried overNa₂SO₄, filtered, and concentrated to provide an oil (587 mg, 1.98mmol), which was used in the next step without any further purification(91% yield). ¹H (CDCl₃ 7.34 (4H, s), 4.68 (2H, s), 4.57 (2H, s), 3.80,600 MHz): δ (2H, t, J=5.2 Hz), 3.56 (2H, t, J=5.3 Hz), 1.69 (1H, br s),0.90 (9H, s), 0.07 (6H, s); ¹³C (CDCl₃ 140.4, 138.3, 128.0, 127.2, 73.2,71.9, 65.4, 150 MHz): δ 63.0, 26.2, 18.6, −5.0.

Example 5D Synthesis of2-tert-butyl-5-{4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]benzyloxy}-4-chloro-2H-pyridazin-3-one

To solution of the product of Example 5C (437 mg, 1.48 mmol) and2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (250 mg, 1.23 mmol)dissolved in anhydrous THF (12 mL) was added solid PPh₃ (485 mg, 1.85mmol) and diisopropyl azodicarboxylate (DIAD, 0.358 mL, 1.85 mmol).After completion of addition the reaction mixture continued to stir atroom temperature. After 20 hours, the reaction mixture was diluted withwater. The aqueous layer was separated and extracted with ethyl acetate(3×). All combined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified usingsilica gel chromatography (4:1 pentane:ethyl acetate) to provide thedesired product 528 mg, 1.10 mmol) in 89% yield. ¹H (CDCl₃ 7.70 (1H, s),7.38 (4H, m), 5.30 (2H, s), 4.58, 600 MHz): δ (2H, s), 3.80 (2H, t,J=5.4 Hz), 3.57 (2H, t, J=5.4 Hz), 1.63 (9H, br s), 0.90 (9H, s), 0.07(6H, s); ¹³C (CDCl₃159.0, 153.7, 138.8, 134.4, 128.3, 127.3, 150 MHz): δ125.1, 118.5, 72.8, 71.7, 71.6, 66.4, 61.9, 29.7, 27.9, 25.6, −5.1; HRMScalcd for C₂₄H₃₇ClN₂O₄Si: 481.228389. found 481.2282.

Example 5E Synthesis of2-tert-butyl-4-chloro-5-[4-(2-hydroxyethoxymethyl)benzyloxy]-2H-pyridazin-3-one

To a solution of the product of Example 5D (528 mg, 1.09 mmol) dissolvedin anhydrous THF (11 mL) was added a solution of TBAF (1.0 M solution inTHF, 1.65 mL, 1.65 mmol) dropwise. After completion of addition thereaction was stirred at room temperature for 1 hour and then quenchedwith water. The aqueous layer was separated and extracted with ethylacetate (3×). All combined organic layers were dried over Na₂SO₄,filtered, and concentrated to provide an oil. The crude material waspurified using silica gel chromatography (4:1 hexanes:ethyl acetate) toprovide the desired product (311 mg, 0.850 mmol) in 78% yield. ¹H(CDCl₃, 600 MHz): δ 7.70 (1H, s), 7.38 (4H, m), 5.30 (2H, s), 4.56 (2H,s), 3.76 (2H, t, J=4.9 Hz), 3.60 (2H, t, J=4.8 Hz), 2.00 (1H, br s),1.61 (9H, br s); ¹³C (CDCl₃159.0, 153.6, 150 MHz): δ 138.8, 134.4,128.2, 127.2, 125.1, 118.3, 72.8, 71.6, 71.6, 66.4, 61.9, 27.8; HRMScalcd for C₁₈H₂₃ClN₂O₄: 367.141911. found 367.1419.

Example 5F Synthesis of toluene-4-sulfonic acid2-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)-benzyloxy]-ethylester

To a solution of the product of Example 5E (200 mg, 0.546 mmol)dissolved in anhydrous dichloromethane (5.50 mL) was added TsCl (125 mg,0.656 mmol), DMAP (100 mg, 0.819 mmol) and triethylamine (0.091 mL,0.656 mmol). The reaction mixture continued stirring at roomtemperature. After 22 hours the reaction mixture was diluted with water.The aqueous layer was separated and extracted with ethyl acetate (3×).All combined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified usingsilica gel chromatography (3:2 pentane:ethyl acetate) to provide thedesired product (232 mg, 0.447 mmol) in 82% yield. ¹H (CDCl₃7.79, 600MHz): δ (2H, d, J=8.3 Hz), 7.71 (1H, s), 7.38 (2H, d, J=8.2 Hz), 7.32(4H, m), 5.30 (2H, s), 4.50 (2H, s), 4.21 (2H, m), 3.69 (2H, m), 2.43(3H, s), 1.63 (9H, br s); ¹³C (CDCl₃ 159.0, 153.7, 144.8, 138.8, 150MHz): δ 134.4, 133.1, 129.8, 128.1, 128.0, 127.2, 125.1, 118.4, 72.8,71.7, 69.2, 67.8, 66.4, 27.9, 21.6; HRMS calcd for C₂₅H₂₉ClN₂O₆:521.150762. found 521.1503.

Example 5G Synthesis of2-tert-butyl-4-chloro-5-[4-(2-fluoro-ethoxymethyl)-benzyloy]-2H-pyridazin-3-one

To a solution of the product of Example 5F (50 mg, 0.096 mmol) inanhydrous acetonitrile (1.0 mL) was added KF (11.2 mg, 0.192 mmol) andKryptofix (72.4 mg, 0.192 mmol). After completion of addition thereaction mixture was heated to 90° C. After 10 minutes, the reactionmixture was cooled down to room temperature and diluted with water. Theaqueous layer was separated and extracted with ethyl acetate (3×). Allcombined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified usingsilica gel chromatography (4:1 pentane:ethyl acetate) to provide thedesired product (28 mg, 0.076 mmol) in 79% yield. ¹H (DMSO-d₆, 600 MHz):δ 8.22 (1H, s), 7.45 (2H, d, J=8.20 Hz), 7.39 (2H, d, J=8.24 Hz), 5.42(2H, s), 4.60 (1H, m), 4.54 (2H, s), 4.52 (1H, m), 3.71 (1H, m), 3.66(1H, m), 1.57 (9H, s); ¹³ 157.8, 153.8, 138.6, C (DMSO-d6, 150 MHz): δ134.6, 127.8, 127.7, 126.2, 115.6, 83.5 (82.4), 71.6, 71.2, 69.1 (69.0),65.3, 27.4; ¹⁹F (DMSO-d₆-221.74 (1F, m), 564 MHz): δ HRMS calcd forC₁₈H₂₂ClFN₂O₃: 369.137575. found 369.1377.

Example 6A Synthesis of 1-(4-hydroxymethylphenoxy)propan-2-one

To a stirred solution of 4-hydroxybenzyl alcohol (1.0 g, 8.06 mmol) inacetone (80 mL) was added potassium carbonate (1.34 g, 9.68 mmol) andchloroacetone (0.771 mL, 9.68 mmol). After completion of addition thereaction mixture was heated to reflux. After 20 hours the reactionmixture was cooled down to room temperature and the solvent was removed.Water and ethyl acetate were added to the crude material. The aqueouslayer was separated and extracted with ethyl acetate (3×, 100 mL). Allcombined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified usingsilica gel chromatography (gradient from 4:1 to 1:1 pentane:ethylacetate) to provide the desired product (0.981 g, 5.45 mmol) in 98%yield. ¹H (CDCl₃, 600 MHz): δ 7.30 (2H, d, J=8.7 Hz), 6.87 (2H, d, J=8.7Hz), 4.63 (2H, d, J=5.7 Hz), 4.54 (2H, s), 2.27 (3H, s), 1.66 (1H, t,J=5.8 Hz); ¹³C (CDCl₃, 150 MHz): δ 205.7, 157.3, 134.3, 128.8, 114.6,73.1, 64.8, 26.6.

Example 6B Synthesis of 1-(4-hydroxymethyl-phenoxy)-propan-2-ol

To a solution of 1-(4-hydroxymethylphenoxy)-propan-2-one (1.26 g, 6.99mmol) dissolved in methanol (60 mL) was added solid NaBH₄ (0.32 g, 8.39mmol). After completion of addition the reaction mixture was stirred atroom temperature overnight. The reaction mixture was diluted with water,and the aqueous layer was extracted with ethyl acetate (3×). Allcombined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil (1.24 g, 6.81 mmol), which was used inthe next step without any further purification (98% yield). ¹H(CDCl₃7.29, 600 MHz): δ (2H, d, J=8.4 Hz), 6.90 (2H, d, J=8.5 Hz), 4.62(2H, s), 4.21 (1H, m), 3.94 (1H, dd, J=9.2, 3.1 Hz), 3.82 (1H, m), 1.29(3H, d, J=6.4 Hz).

Example 6C Synthesis of2-tert-butyl-4-chloro-5-[4-(2-hydroxypropoxy)benzyloxy]-2H-pyridazin-3-one

To solution of the product of Example 6B (269 mg, 1.48 mmol) and2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (250 mg, 1.23 mmol)dissolved in anhydrous THF (18.5 mL) was added solid PPh₃ (485 mg, 1.85mmol) and DIAD (0.358 mL, 1.85 mmol). After completion of addition thereaction mixture continued to stir at room temperature. After 20 hours,the reaction mixture was diluted with water. The aqueous layer wasseparated and extracted with ethyl acetate (3×). All combined organiclayers were dried over Na₂SO₄, filtered, and concentrated to provide anoil. The crude material was purified using silica gel chromatography(1:1 pentane:ethyl acetate) to provide the desired product (234 mg,0.634 mmol) in 51% yield. ¹H (CDCl₃ 7.71 (1H, s), 7.33 (2H, d, 600 MHz):δ J=8.7 Hz), 6.94 (2H, d, J=8.7 Hz), 5.24 (2H, s), 4.19 (1H, m), 3.95(1H, dd, J=9.2, 3.1 Hz), 3.81 (1H, dd, J=9.2, 7.7 Hz), 1.62 (9H, s) 1.29(3H, d, J=6.4 Hz).

Example 6D Synthesis of toluene-4-sulfonic acid2-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)-phenoxy]-1-methyl-ethylester

To a solution of the product of Example 6C (200 mg, 0.546 mmol)dissolved in anhydrous dichloromethane (6.0 mL) was added TsCl (125 mg,0.656 mmol), DMAP (100 mg, 0.819 mmol) and triethylamine (0.0914 mL,0.656 mmol). The reaction mixture continued stirring at roomtemperature. After 22 hours the reaction mixture was diluted with water.The aqueous layer was separated and extracted with ethyl acetate (3×).All combined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified usingsilica gel chromatography (70:30 pentane:ethyl acetate) to provide thedesired product (166 mg, 0.319 mmol) in 58% yield. ¹H (CDCl₃7.80 (2H, d,600 MHz): δ J=8.3 Hz), 7.72 (1H, s), 7.32 (2H, d, J=7.9 Hz), 7.29 (2H,d, J=8.7 Hz), 6.74 (2H, d, J=8.7 Hz), 5.22 (2H, s), 4.19 (1H, m), 4.02(1H, dd, J=10.4, 6.0 Hz), 3.93 (1H, dd, J=10.4, 4.5 Hz), 2.44 (3H, s),1.63 (9H, s) 1.42 (3H, d, J=6.5 Hz); ¹³C (CDCl₃ 158.9, 150 MHz): δ158.3, 153.6, 144.6, 133.8, 129.6, 128.8, 127.8, 127.4, 125.1, 118.0,114.7, 76.8, 71.5, 69.7, 66.2, 27.7, 21.5, 17.6; HRMS calcd forC₂₅H₂₉ClN₂O₆S: 521.150762. found 521.1505.

Example 6E Synthesis of2-tert-butyl-4-chloro-5-[4-(2-fluoropropoxy)benzyloy]-2H-pyridazin-3-one

To a solution of the product of Example 6E (50 mg, 0.096 mmol) inanhydrous acetonitrile (1.0 mL) was added KF (11.2 mg, 0.192 mmol) andKryptofix (72.4 mg, 0.192 mmol). After completion of addition thereaction mixture was heated to 90° C. After 40 minutes, the reactionmixture was cooled down to room temperature and diluted with water. Theaqueous layer was separated and extracted with ethyl acetate (3×). Allcombined organic layers were dried over Na₂SO₄, filtered, andconcentrated to provide an oil. The crude material was purified using apreparative silica gel thin layer chromatography plate (4:1pentane:ethyl acetate) to isolate the desired product (12.5 mg, 0.034mmol) in 41% yield (based on recovererd starting material), in additionto unreacted starting material (5.8 mg, 0.011 mmol). ¹H (CDCl₃, 600MHz): δ 7.73 (1H, s) 7.34 (2H, d, J=8.6 Hz), 6.95 (2H, d, J=8.6 Hz),5.25 (2H, s), 5.06-4.96 (1H, m), 4.06 (2H, m), 1.63 (9H, s) 1.47 (3H,dd, J=6.4, 23.6 Hz); ¹³C (DMSO-d₆, 158.4, 157.8, 153.9, 129.8, 127.6,126.2, 115.5, 114.6, 89.9150 MHz): δ (88.0), 71.2, 70.4 (70.3), 65.3,27.4, 16.9 (16.8); ¹⁹F (DMSO-d₆, −178.20 (1F, m); 564 MHz): δ HRMS calcdfor C₁₈H₂₂ClFN₂O₃: 369.137575. found 369.1370.

Example 7A Synthesis of 4-(3-oxobutyl)benzoic acid methyl ester

To a solution of methyl-4-bromobenzoate (1.0 g, 4.65 mmol) intriethylamine (13 mL) was added 3-buten-2-ol (1 mL, 11.63 mmol),palladium (II) acetate (0.104 g, 0.465 mmol), and thentriphenylphosphine (0.244 g, 0.93 mmol). The reaction was stirred in a75° C. oil bath overnight under nitrogen atmosphere. Monitoring by TLC(3:1 hexane:ethyl acetate) showed the product and aryl bromide. Thereaction was cooled to room temperature and then concentrated. Water wasthen added followed by extraction with ethyl acetate. The organic layerwas washed with water and brine, dried over Na₂SO₄, filtered andconcentrated. The crude product was purified by flash columnchromatography (5:1 to 3:1 hexane:ethyl acetate) to obtain the product(250 mg, 26% yield). ¹H NMR (600 MHz, CDCl₃): δ 7.95 (d, 2H, J=8.4 Hz),7.25 (d, 2H, J=8.4 Hz), 3.90 (s, 3H), 2.95 (t, 2H, J=7.45 Hz), 2.77 (t,2H, J=7.68 Hz), 2.14 (s, 3H).

Example 7B Synthesis of2-tert-butyl-4-chloro-5-[4-(3-hydroxybutyl)benzyloxy]-2H-pyridazin-3-one

To a solution of the product of Example 7A (505 mg, 2.447 mmol) in THF(19 mL) at 0° C. was added a 1M solution (in THF) of lithium aluminumhydride (12.2 mL, 12.237 mmol) dropwise. After completion of additionthe ice bath was removed and the reaction was stirred at roomtemperature for 1 hour under nitrogen atmosphere. Then, in succession,was added water (183 μL), 15% NaOH solution (183 μL), and water (548μL). The reaction stirred for an additional 15 minutes before it wasfiltered and washed with THF. The filtrate was then concentrated underreduced pressure to obtain 4-(4-hydroxymethyl-phenyl)butan-2-ol as abrown oil (314 mg, 71% yield). Then to a solution of2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (234 mg, 1.155 mmol)in THF (45 mL) was added 4-(4-hydroxymethylphenyl)butan-2-ol (312 mg,1.732 mmol), triphenylphosphine (454 mg, 1.732 mmol), and thendiisopropyl azodicarboxylate (DIAD, 335 μL, 1.732 mmol). The reactionwas stirred at room temperature overnight under nitrogen atmosphere.Thin layer chromatography (100% ethyl acetate) indicated consumption ofthe pyridazinone starting material and the reaction was concentrated.The crude material was purified by flash column chromatography (4:1hexane:ethyl acetate to 100% ethyl acetate) to obtain a clear oil (200mg, 48% yield). ¹H NMR (600 MHz, CDCl₃): δ 7.73 (s, 1H), 7.32 (d, 2H,J=8.0), 7.24 (d, 2H, J=8.0), 5.30 (s, 1H), 5.27 (s, 2H), 3.83 (m, 1H),2.80-2.76 (m, 1H), 2.71-2.66 (m, 1H), 1.63 (s, 9H), 1.23 (d, 3H, J=6.2);¹³C (CDCl₃ 159.3, 153.9, 143.2, 132.5, 129.2, 127.6, 125.4, 150 MHz): 5HRMS calcd for 0118.5, 73.4, 67.6, 66.6, 40.9, 32.0, 28.1, 23.9.₁₉H₂₅ClN₂O₃: 365.162647. found 365.1624.

Example 7C Synthesis of toluene-4-sulfonic acid3-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)-phenyl]-1-methylpropylester

To a solution of the product of Example 7B (200 mg, 0.548 mmol) inpyridine (10 mL) was added p-toluenesulfonyl chloride (209 mg, 1.096mmol). The reaction was stirred at room temperature overnight undernitrogen atmosphere. Monitoring by LC-MS showed a 1:1 mixture ofstarting material and product. The reaction was diluted with ethylacetate and washed with 5% CuSO₄ until a light blue aqueous solution wasmaintained. The organic layer was then dried over Na₂SO₄, filtered, andconcentrated. The crude material was purified by flash columnchromatography (3:1 hexane:ethyl acetate to 100% ethyl acetate) torecover the starting material (90 mg) and the product as a clear oil (74mg, 47% yield based on recovered starting material). ¹H NMR (600 MHz,CDCl₃): 7.80 (d, 2H, J=8.3 Hz), 7.72 (s, 1H), 7.33 (d, 2H, J=8.0 Hz),7.30 (d, 2H, J=8.1 Hz), 7.13 (d, 2H, J=8.1 Hz), 5.27 (s, 2H), 4.66 (m,1H), 2.65 (m, 1H), 2.54 (m, 1H), 2.45 (s, 3H), 1.94 (m, 1H), 1.81 (m,1H), 1.63 (s, 9H), 1.26 (s, 3H).

Example 7D Synthesis of2-tert-butyl-4-chloro-5-[4-(3-fluorobutyl)benzyloxy]-2H-pyridazin-3-one

To a solution of the product of Example 7C (18.2 mg, 0.035 mmol) inacetonitrile (400 μl) was added potassium fluoride (4.1 mg, 0.070 mmol)and K222 (26.4 mg, 0.070 mmol). The reaction was stirred at 90° C. for20 minutes under nitrogen atmosphere, monitoring by LC-MS. The reactionwas then cooled to room temperature and concentrated under reducedpressure. The crude material was purified by preparative thin layerchromatography (4:1 hexane:ethyl acetate as eluant) to obtain theproduct as an oil (5 mg, 39% yield). ¹H NMR (600 MHz, CDCl₃): δ 7.70 (s,1H), 7.34 (d, 2H, J=7.9 Hz), 7.24 (d, 2H, J=8.0 Hz), 5.28 (s, 2H),4.71-4.60 (m, 2H), 2.84-2.80 (m, 1H), 2.73-2.69 (m, 1H), 2.02-1.93 (m,1H), 1.87-1.77 (m, 1H), 1.63 (s, 9H), 1.35 (dd, 3H, J=6.2 and 23.9 Hz);¹³C (CDCl₃159.1, 153.8, 150 MHz): δ 142.4, 132.5, 129.0, 127.4, 125.2,118.3, 90.4 (89.3), 71.9, 66.3, 38.5 (38.4), 31.1 (31.0), 27.9, 21.1(21.0); ¹⁹F (CDCl₃-174.7, 564 MHz): δ (1F, m); HRMS calcd forC₁₉H₂₃ClFN₂O₂: 367.158310. found 367.1582.

Example 8A Synthesis of 4-[2-hydroxyethoxymethyl]benzoic acid methylester tetradeuterate

To a flame-dried 2-neck flask was added a solution ofmethyl-4-(hydroxymethyl)benzoate (2.5 g, 15 mmol) in dichloromethane (30mL). The reaction was purged with nitrogen and brought to −5° C. A dewarcondenser (also flame-dried) containing a dry ice/acetone bath (−78° C.)was affixed to the flask and ethylene oxide-tetradeuterate was added(−55 drops). Then BF₃Et₂O (510 μL, 0.0041 mmol) was added dropwise andthe reaction stirred at −5° C. for 35 minutes under nitrogen atmosphere.Monitoring by TLC (100% ethyl acetate) showed complete consumption ofthe starting material. The reaction was warmed to room temperature andvented to remove any excess ethylene oxide gas. The reaction was thendiluted with brine and extracted with dichloromethane (2 times). Thecombined organics were dried over Na₂SO₄, filtered, and concentratedunder reduced pressure to obtain a crude oil. Purification by flashcolumn chromatography (4:1 pentane:ethyl acetate) provided the productas a clear oil (520 mg, 16% yield). ¹H NMR (600 MHz, CDCl₃) δ 8.02 (d,2H, J=8.2 Hz), 7.41 (d, 2H, J=8.1 Hz), 4.62 (s, 2H), 3.92 (s, 3H); ¹³CNMR (150 MHz, CDCl₃167.1, 143.5, 130.8) δ 129.9, 127.5, 72.8, 52.4.

Example 8B Synthesis of4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]benzoic acid methylester tetradeuterate

To a solution of the product of Example 8A (500 mg, 2.334 mmol) in DMF(23 mL) was added tert-butyldimethylsilyl chloride (528 mg, 3.501 mmol)and imidazole (238 mg, 3.501). The reaction was stirred at roomtemperature for 5 hours under nitrogen atmosphere, monitoring by TLC(3:1 pentane:ethyl acetate). Another 0.5 eq. portion oftert-butyldimethylsilyl chloride (176 mg) and imidazole (79 mg) wereadded and the resultant mixture stirred at room temperature overnight.The majority of the starting material was consumed in 16 hours, asindicated by thin layer chromatography. The reaction was diluted withwater and extracted with ethyl acetate (2 times). The combined organiclayers were dried over Na₂SO₄, filtered, and concentrated under reducedpressure to obtain a crude oil which was purified by passage throughthick pad of silica gel (3:1 pentane:ethyl acetate) to obtain theproduct as a clear oil (602 mg). ¹H NMR (600 MHz, CDCl₃): 8.00 (d, 2H,J=8.3 Hz), 7.40 (d, 2H, J=8.5 Hz), 4.62 (s, 2H), 3.90 (s, 3H), 0.90 (s,9H), 0.06 (s, 6H).

Example 8C Synthesis of{4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]phenyl}methanolhexadeuterate

To a solution of the product of Example 8B (610 mg, 1.857 mmol) in THE(19 mL) at 0° C. was added a 1M solution (in THF) of lithium aluminumdeuteride (1.9 mL, 1.857 mmol) dropwise. After completion of additionthe ice bath was removed and the reaction was stirred at roomtemperature for 3.5 hours under nitrogen atmosphere, monitoring by TLC(3:1 pentane:ethyl acetate). The reaction was then diluted with waterand extracted with ethyl acetate (2 times). The combined organics weredried over Na₂SO₄, filtered, and concentrated under reduced pressure toobtain a clear oil (482 mg, 86% yield). The material was taken to thenext step without further purification. ¹H NMR (600 MHz, CDCl₃): 7.33(s, 4H), 4.56 (s, 2H), 0.89 (s, 9H), 0.06 (s, 6H).

Example 8D Synthesis of2-tert-butyl-4-chloro-5-{4-[2-(tert-butyldimethylsilanyloxy)ethoxymethyl]benzyloxy}-2H-pyridazin-3-onehexadeuterate

To a solution of 2-tert-butyl-4-chloro-5-hydroxy-2H-pyridazin-3-one (212mg, 1.047 mmol) in THF (15 mL) was added the product of Example 8C (475mg, 1.570 mmol), triphenylphosphine (412 mg, 1.570 mmol), and thendiisopropyl azodicarboxylate (DIAD, 304 μL, 1.570 mmol). The reactionwas stirred at room temperature for 2 hours under nitrogen atmosphere.Thin layer chromatography (1:1 hexane:ethyl acetate) indicatedconsumption of the pyridazinone starting material and the reaction wasconcentrated in vacuo. The crude material was purified by flash columnchromatography (90:10 pentane:ethyl acetate) to obtain a clear oil (336mg, 66% yield). ¹H NMR (600 MHz, CDCl₃): 7.70 (s, 1H), 7.39 (m, 4H),4.58 (s, 2H), 1.63 (s, 9H), 0.90 (s, 9H), 0.07 (s, 6H); HRMS calcd forC₂₄H₃₁D₆ClN₂O₄Si: 509.24738. found 509.2480.

Example 8E Synthesis of2-tert-butyl-4-chloro-5-[4-(2-hydroxyethoxymethyl)benzyloxy]-2H-pyridazin-3-onehexadeuterate

To a solution of the product of Example 8D (330 mg, 0.677 mmol) in THF(7 mL) was added a 1M solution (in THF) of tetrabutylammonium fluoride(1 mL, 1.016 mmol) dropwise. The reaction was stirred at roomtemperature for 2 hours under nitrogen atmosphere, monitoring by TLC(1:1 hexane:ethyl acetate). The reaction was then concentrated underreduced pressure and passed through a thick pad of silica (100% ethylacetate) to obtain the product as an oil containing a minor percentageof the corresponding silanol. The material was taken to the next stepwithout further purification. ¹H NMR (600 MHz, CDCl₃): 7.72 (s, 1H),7.41 (s, 4H), 4.59 (s, 2H), 1.64 (s, 9H); ¹³C NMR (150 MHz, rt,CDCl₃):159.2, 153.9, 139.5, 134.5, 128.5, 127.5, 125.3, 118.6, 73.0,66.6, 28.1; HRMS calcd for C₂₅H₂₃D₆ClN₂O₆S: 549.169754. found 549.1705.

Example 8F Synthesis of toluene-4-sulfonic acid2-[4-(1-tert-butyl-5-chloro-6-oxo-1,6-dihydro-pyridazin-4-yloxymethyl)-benzyloxy]ethylester hexadeuterate

To a solution of the product of Example 8E (250 mg, 0.670 mmol) indichloromethane (7 mL) was added p-toluenesulfonyl chloride (153 mg,0.805 mmol), N,N-dimethylaminopyridine (DMAP, 98 mg, 0.805 mmol), andtriethylamine (140 μL, 1.005 mmol). The reaction was stirred at roomtemperature overnight under nitrogen atmosphere. Thin layerchromatography (1:1 hexane:ethyl acetate) indicated almost completeconsumption of the alcohol. The reaction was concentrated under reducedpressure and the crude material was purified by flash chromatography(2:1 hexane:ethyl acetate to 1:1 hexane:ethyl acetate to 100% ethylacetate) to recover the starting material (9 mg) and the product (261mg, 77% yield based on recovered starting material) as a clear oil. ¹HNMR (600 MHz, CDCl₃): 7.76 (d, 2H, J=8.3 Hz), 7.73 (s, 1H), 7.36 (d, 2H,J=8.1 Hz), 7.29 (m, 4H), 4.47 (s, 2H), 2.40 (s, 3H), 1.61 (s, 9H); ¹³CNMR (150 MHz, rt, CDCl₃): 159.0, 153.8, 145.0, 138.5, 134.4, 133.1,129.9, 128.1, 128.0, 127.3, 125.2, 118.1, 72.7, 71.0, 37.0, 63.4, 28.0,21.7.

Example 8G

To a solution of the product of Example 8F (14 mg, 0.027 mmol) inacetonitrile (300 μL) was added potassium fluoride (3.1 mg, 0.053 mmol)and K222 (20 mg, 0.053 mmol). The reaction was stirred at 90° C. for 10minutes under nitrogen atmosphere, monitoring by TLC (1:1 hexane:ethylacetate). The reaction was then cooled to room temperature andconcentrated under reduced pressure. The crude material was purified bypreparative TLC (2:1 hexane:ethyl acetate) to obtain the product as anoil (6.2 mg, 62% yield). ¹H NMR (600 MHz, CDCl₃): 7.70 (s, 1H), 7.40 (s,4H), 4.61 (s, 2H), 1.63 (s, 9H); ¹³C NMR (150 MHz, rt, CDCl₃): 158.5,153.1, 138.2, 133.8, 127.7, 126.8, 124.6, 117.8, 72.4, 65.9, 27.3; ¹⁹FNMR (564 MHz, CDCl₃): −225.2 (m, 1F).

Radiosynthetic and Purification Procedures for Preparation of Fenazaquinand Pyridaben Complexes Radiolabeled with the Fluorine-18 Radionuclide

The Fluorine-18 (¹⁸F) used in the research is produced via the protonbombardment of enriched Oxygen-18 (¹⁸O) as H₂ ¹⁸O with usingapproximately 10 MeV protons by PETnet (Woburn, Mass.). The expressionfor this nuclear reaction is: O¹⁸ (p, γ)¹⁸F.

For all of the radiosynthetic reactions a similar procedure was used.All glassware was silanized to preclude adhesion of the material to thevessel walls and optimize transfers. A dedicated, specific HPLC unit wasused for purification for all compounds. A dedicated specific HPLC unitwas used for radioanalytical analyses of final product.

The ¹⁸F typically was received from the supplier deposited on aprocessed column (¹⁸F column) encased in lead shielding. The ¹⁸F columncontained the sodium salt coordinated to either alumina or a quaternaryammonium salt housed in a glass column. The column ends are connected toTygon™ tubing with male and female Luer™ lock fittings. The ¹⁸F isremoved from the column using the following method.

1. A solution of 15 mg of potassium carbonate (K₂CO₃) in 1 mL ofdistilled/deionized water (H₂O) and a solution of 90 mg of4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (Kryptofix™;K222) dissolved in 4 mL of anhydrous acetonitrile (CH₃CN) were combinedand gently stirred, ensuring the layers did not separate, forming thecolumn eluting solution (CES).2. A one mL aliquot of the CES was extracted from the vial described instep three using a 3 mL syringe and the syringe was attached to the maleLuer™ lock of the Tygon™ tubing connected to the ¹⁸F column.3. A narrow gauge needle was attached to the female Luer™ lock of theother Tygon™ tubing connected to the ¹⁸F column, and the needle wasinserted through the rubber septum fitted to a 15 mL 24/40 Pyrex™pear-shaped glass flask.4. The 15 mL pear shaped flask was vented with a needle and the flaskwas flushed with dry nitrogen. The flushing needle was connected to avacuum line and the flow adjusted such that CES was slowly drawn throughthe ¹⁸F column into the 15 mL pear-shaped flask.5. The vacuum and N₂ gas flow were adjusted such that the contents ofthe flask were reduced to dryness. Anhydrous CH₃CN (1 mL) was added viasyringe to the flask, using vacuum to drive the transfer. The vacuum andN₂ gas flow were balanced to remove the acetonitrile. This procedure wasrepeated twice, after which point the vacuum was removed.6. The contents of the flask were removed via syringe and theradioactivity was quantified. The ¹⁸F solution was used directly inradiolabeling syntheses.

The next steps describe the radiolabeling of the fenazaquin andpyridaben analogs with ¹⁸F. As previously stated these steps were thesame for each of the compounds. The following reaction scheme depicts arepresentative scenario for all of the ¹⁸F-fenazaquin and pyridabenanalogs:

7. The toluenesulfonate ester precursor to the desired fenazaquin orpyridaben analog (2.5 mg) was dissolved in CH₃CN (0.5 mL) in a conicalsilanized 5 mL Wheaton™ glass vial with a magnetic stirring bar. Thevial was immersed in a oil bath heated at 90° C. The solution of the ¹⁸Fdescribed above was added to the reaction vial the resultant mixture washeated at 90° C. for 30 minutes.8. The contents were transferred to a 50 mL silanized round bottom flaskcontaining distilled/deionized water (25 mL), and the contents of theflask are removed via syringe, and deposited on a Waters™ Oasis HLB(hydrophilic-lipophilc balance) column, allowing unreacted fluoride andundesired salts to pass through with the eluate.9. The organic components were eluted from the column into a conical 5mL vial using dichloromethane, (3 mL, CH₂Cl₂). The eluant was purifiedvia preparative HPLC (Phenomenex LUNA C-18 column 250×10 mm, 5 uparticle, 100A pore. gradient elution 90/10 H₂O/CH₃CN—CH₃CN). Theappropriate fractions were concentrated and analyzed for radiochemicalyield and radiochemical purity (analytical HPLC). The solution wasconcentrated to dryness in vacuo, and dissolved in the appropriatevolume of 10% ethanolic saline for injection and/or biological studies.

Additionally, the following compounds may be prepared following thedescribed procedures:

Example 1 Deguelin Analogs

Synthesis of 4′-bromo-rot-2′-enonic acid

Rotenone (5.0 g, 12.7 mmol) dissolved in dichloromethane (30 mL) isadded rapidly to a cooled (−10° C.) solution of boron tribromide (3.15g, 12.7 mmol) in dichloromethane (32.7 mL). The reaction mixture isstirred for exactly two minutes and then evaporated to dryness. Theresulting brown crude material is dissolved in the minimum amount ofmethanol and cooled to 0° C. to initiate crystallization. Brown crystalsare collected and dried to afford 4′-bromo-rot-2′-enonic acid (3.24 g).

Synthesis of 4′-hydroxy-rot-2′-enonic acid

Silver oxide (1.0 g, 4.24 mmol) is added to a solution of4′-bromo-rot-2′enonic acid (2.0 g, 4.24 mmol) dissolved in acetone (80mL). After completion of addition the reaction mixture continues to stirin the dark. After 24 h the reaction mixture is filtered through celiteand the filtrate is concentrated to yield a yellow oil. The crudematerial is dissolved in the minimum amount of dichloromethane andcooled to 0° C. to initiate crystallization. 4′-hydroxy-rot-2′enonicacid (1.0 g) can be collected as yellow crystals.

Synthesis of (6aS,12aS)-7′-hydroxydeguelin

Solid PhSe—Cl (370.87 mg, 1.94 mmol) is added to a cooled (−30° C.)solution of 4-hydroxy-rot-2′enonic acid (725.5 mg, 1.71 mmol) indichloromethane (20 mL). After completion of addition, the reactionmixture is allowed to warm to room temperature over 2 h and continues tostir at room temperature for an additional hour. After three hours oftotal reaction time the reaction mixture is concentrated to yield ayellow oil. The crude material is dissolved in THF (20 mL) and cooled to0° C. Hydrogen peroxide (30% in water, 0.354 mL) is added. Aftercompletion of addition the reaction mixture stirs at 0° C. for one hourand then stirs at room temperature overnight. The next day, the reactionmixture is diluted with diethyl ether. The organic layer is separatedand washed with 5% NaHCO₃ (2×), dried over Na₂SO₄ and concentrated toyield (6aS,12aS)-7′-hydroxydeguelin as a yellow amorphous solid.

Synthesis of (6aS,12aS)-7′-toluenesulfonyldeguelin

To a stirring solution of (6aS,12aS)-7′hydroxy deguelin (30 mg, 0.073mmol) in dichloromethane (1.5 mL) is added TsCl (15.3 mg, 0.080 mmol)and pyridine (6.47 μL, 0.080 mmol). After completion of addition, thereaction mixture continues to stir at room temperature. After 48 h thereaction is ˜50% complete according to LCMS and is concentrated. Thecrude material is purified using silica gel chromatography (gradientfrom 100% dichloromethane to 25% acetone in dichloromethane) to yield(6aS,12aS)-7′-toluenesulfonyldeguelin as a yellow oil.

Synthesis of (6aS,12aS)-7′-methanesulfonyldeguelin

To a stirring solution of (6aS,12aS)-7′-hydroxydeguelin (50 mg, 0.122mmol) in dichloromethane (0.5 mL) is added MsCl (9.48 pit, 0.122 mmol)and triethylamine (17.0 μL, 0.122 mmol). After completion of additionthe reaction mixture continues to stir at room temperature. After 3 h,additional equivalents of MsCl and triethylamine are added because thereaction is only ˜80% complete. After 24 h the reaction is complete anddiluted with water. The aqueous layer is extracted with dichloromethane.All combined organic layers are dried over Na₂SO₄, filtered, andconcentrated to yield a yellow oil. Silica gel chromatography (gradientfrom 100% dichloromethane to 5% acetone in dichloromethane) affords(6aS,12aS)-7′-methanesulfonyldeguelin (48 mg) as a yellow oil.

Synthesis of (6aS,12aS)-7′-[¹⁸F]fluorodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and(6aS,12aS)-7′-methanesulfonyldeguelin (2 mg) is added in one portion.The vial is recapped and heated at 65° C. for 30 minutes. After cooling,the vial is diluted with water (4 mL) and passed through a silica gelcartridge (pre-loaded Waters Light C-18 Sep-Pak) to load the sample. Thecartridge is rinsed with water and eluted with CH₃CN (2 mL). Theacetonitrile is evaporated and the residue is purified via HPLC toafford pure carrier-free (6aS,12aS)-7′-[¹⁸F]fluorodeguelin.

Synthesis of (6aS,12aS)-7′-[¹⁸F]fluorodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and(6aS,12aS)-7′-toluenesulfonyldeguelin (2 mg) is added in one portion.The vial is recapped and heated at 65° C. for 30 minutes. After cooling,the vial is diluted with water (4 mL) and passed through a silica gelcartridge (pre-loaded Waters Light C-18 Sep-Pak) to load the sample. Thecartridge is rinsed with water and eluted with CH₃CN (2 mL). Theacetonitrile is evaporated and the residue is purified via HPLC toafford pure carrier (6aS,12aS)-7′-[¹⁸F]fluorodeguelin.

Synthesis of (−)-rot-2′enonic acid

Solid sodium cyanoborohydride (264 mg, 4.20 mmol) is added to a solutionof 4′-bromo-rot-2′enonic acid (500 mg, 1.05 mmol) dissolved in HMPA.After

completion of addition the reaction mixture is heated to 70° C. After2.5 h the reaction is cooled down to room temperature and diluted withwater. The aqueous layer is extracted with a diethyl ether/hexanemixture (3/1). The organic layer is dried over Na₂SO₄, filtered, andconcentrated to yield a clear oil. Silica gel chromatography (gradientfrom 20% hexane in dichloromethane to 5% acetone in dichloromethane)affords (−)-rot-2′enonic acid (162.2 mg) as a clear oil.

Synthesis of (6aS,12aS)-deguelin

Solid PhSe—Cl (185 mg, 0.972 mmol) is added to a cooled (−30° C.)solution of (−)-rot-2′enonic acid (350 mg, 0.884 mmol) indichloromethane (10.5 mL). After completion of addition the reactionmixture is allowed to warm to room temperature over 2 h and continues tostir at room temperature for an additional hour. After three hours oftotal reaction time the reaction mixture is concentrated to yield ayellow oil. The crude material is dissolved in THF (10.5 mL) and cooledto 0° C. Hydrogen peroxide (30% in water, 0.177 mL) is added. Aftercompletion of addition the reaction mixture continues to stir at 0° C.for one hour and then stirs at room temperature overnight. The next daythe reaction mixture is diluted with diethyl ether. The organic layer isseparated and washed with 5% NaHCO₃ (2×), dried over Na₂SO₄ andconcentrated to yield (6aS,12aS)-deguelin as a yellow amorphous solid.

Synthesis of (6aS)-deguelin enol ether

To a solution of deguelin (245 mg, 0.622 mmol) in methanol (20 ml) isadded p-TsOH monohydrate (118.3 mg, 0.622 mmol) and trimethylorthoformate (68.14 μL, 0.622 mmol). After completion of addition thereaction mixture is heated to reflux for 8 h and then continues to stirat room temperature overnight. The next day the reaction mixture isdiluted with water. The aqueous layer is extracted with ethyl acetate.Combined organic layers are washed with sat. NaHCO₃, dried over Na₂SO₄and concentrated to yield (6aS)-deguelin enol ether as a yellowamorphous solid.

Synthesis of (6aS)-4′,5′-dihydro-4′,5′epoxydeguelin enol ether

To a cooled (0° C.) solution of (6aS)-deguelin enol ether (50 mg, 0.123mmol) in dichloromethane (0.5 ml) is added m-CPBA (45 mg, 0.184 mmol).After completion of addition the reaction mixture continues to stir atroom temperature. After 6.5 h the reaction is diluted with water. Theaqueous layer is extracted with dichloromethane. All combined organiclayers are dried over Na₂SO₄, concentrated and purified using silica gelchromatography (gradient 100 dichloromethane to 30%

in dichloromethane) to yield (6aS)-4′,5′-dihydro-4′,5′epoxydeguelin enolether. Synthesis of (6aS,12aS)-4′,5′,-dihydro-4′[¹⁸F]flouro,5′hydroxydeguelin:

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and(6aS)-4′5′-dihydro-4′,5′epoxydeguelin enol ether (2 mg) is added in oneportion. The vial is recapped and heated at 65° C. for 30 minutes. Aftercooling down to room temperature, a solution of trifluoroacteic acid(500 mL) and water (300 mL) is slowly added. The reaction vessel isclosed and allowed to stand at 60° C. for 2 min. After cooling to roomtemperature, the vial is diluted with water (4 mL) and passed through asilica gel cartridge (pre-loaded Waters Light C-18 Sep-Pak) to load thesample. The cartridge is rinsed with water and eluted with CH₃CN (2 mL).The acetonitrile is evaporated and the residue is purified via HPLC toafford pure carrier-free (6aS, 12aS)-4′,5′,-dihydro-4′[¹⁸F]flouro,5′hydroxydeguelin.

Synthesis of (6aS,12aS)-2-0-desmethyldeguelin

(6aS,12aS)-Deguelin (251 mg, 0.638 mmol) and sodium methanethiolate (125mg, 1.78 mmol) are dissolved in 4 ml of N,N-dimethylacetamide and heatedat 80° C. for 26 h. The reaction mixture is diluted to 50 ml with waterand extracted with dichloromethane. The aqueous layer is then acidifiedwith 5% HCl and extracted again with dichloromethane. All of the organiclayers are dried over Na₂SO₄, concentrated, and purified using silicagel chromatography (100% dichloromethane to 30% acetone indichloromethane) to yield (6aS,12aS)-2-O-desmethyldeguelin.

Synthesis of (6aS,12aS)-2[¹⁸F]fluoromethoxydeguelin

[¹⁸F]F is made by irradiating [¹⁸O]water (>94 at %; 400 μL) in silvertarget chambers with 17 meV protons from a 103 cm AVF cyclotron. Typicalirradiations are of 45 min. duration with a beam current of 10 mAyielding about 18 GBq [¹⁸F] fluoride. After irradiation, the targetwater is transported via silicone tubing to the synthesis apparatus.This apparatus consists of a borosilicate vessel (5 ml), which

contains potassium carbonate (5 mg, 36 μmol) and K2.2.2 (18 mg, 48 μmol)in acetonitirile (1 mL). The target water is evaporated under reducedpressure and He-flow. Three portions of acetonitrile are added at 110°C. The reaction chamber is allowed to cool down to room temperature anddibromomethane (50 μL) in acetonitrile (1 ml) is added to the dry¹⁸F/K2.2.2-mixture. The reaction mixture is heated again at 110° C. andthe volatile products were transferred to a preparative GC with He as acarrier. The column is heated to 100° C. and [¹⁸F]CH₂BrF is separatedfrom solvents and other reagents.

Freshly obtained [¹⁸F]CH₂BrF is added to a vial containing(6aS,12aS)-2-0-desmethyldeguelin (2 mg) in ACN (150 uL). The vial isrecapped and heated at 65° C. for 30 minutes. After cooling, the vial isdiluted with water (4 mL) and passed through a silica gel cartridge(pre-loaded Waters Light C-18 Sep-Pak) to load the sample. The cartridgeis rinsed with water and eluted with CH₃CN (2 mL). The acetonitrile isevaporated and the residue is purified via HPLC to afford pure carrier(6aS,12aS)-2[¹⁸F]fluoromethoxydeguelin.

Synthesis of (6aS,12aS)-2[¹⁸F]fluoroethoxydeguelin

Toluenesulfonylchloride (38.3 g, 0.201 mol) and pyridine (15.9 g, 0.201mol) are added to a solution of ethane-1,2-diol (5 g, 0.081 mol)) indichloromethane (100 mL) at 0° C. After completion of addition thereaction stirs at room temperature overnight. In the morning thereaction mixture is diluted with water. The aqueous layer is extractedwith dichloromethane, dried over Na₂SO₄, and concentrated. The crudematerial is purified using silica gel chromatography (4:1 hexanes ethylacetate to 100% ethyl acetate) to obtain ditosyl ethane in good yield.

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (8.5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 340 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and 1,2-ditoluenesulfonatoethane (3.4 mg) is added in one portion. The vial is recapped and heatedat 85° C. for 30 minutes. After cooling down to room temperature, thesolvent is removed under reduced pressure to yield the [¹⁸F]fluoroethyltosylate precursor (2.0 mg, 0.010 mmol).(6aS,12aS)-2-0-desmethyldeguelin (3.8 mg, 0.010 mmol) andtetrabutylammonium hydroxide (2.6 mg, 0.010 mmol) are added in DMF (0.25mL) and the reaction mixture is heated again to 60° C. After 15 min. thereaction mixture is cooled down to room temperature, the vial is dilutedwith water (4 mL) and passed through a silica gel cartridge (pre-loadedWaters Light C-18 Sep-Pak) to load the sample. The cartridge is rinsedwith water and eluted with CH₃CN (2 mL). The acetonitrile is evaporatedand the residue is purified via HPLC to afford pure carrier(6aS,12aS)-2[¹⁸F]fluoroethoxydeguelin.

Synthesis of (6aS)-4′,5′-dihydro-5′-hydroxydeguelin enol ether

(6aS)-4′,5′-dihydro-4′,5′-epoxydeguelin enol ether (1.0 g, 2.35 mmol) isdissolved in THF (20 mL) and cooled to 0° C. Lithium aluminum hydride(2.35 mL of 1 M THF solution) is added dropwise to the stirringsolution. After completion of addition the reaction mixture stirs atroom temperature overnight. In the morning the reaction is quenched withwater. The aqueous layer is extracted with ethyl acetate. All organiclayers are dried over Na₂SO₄, concentrated and purified using silica gelchromatography (100% dichloromethane to 30% acetone in dichloromethane)to yield (6aS)-4′,5′-dihydro-5′-hydroxydeguelin enol ether.

Synthesis of (6aS)-4′,5′-dihydro-5′toluenesulfonyldeguelin enol ether

To a stirring solution of (6aS)-4′,5′-dihydro-5′-hydroxydeguelin enolether (31 mg, 0.073 mmol) in dichloromethane (1.5 mL) is added TsCl(15.3 mg, 0.080 mmol) and pyridine (6.47 μL, 0.080 mmol). Aftercompletion of addition the reaction mixture continues to stir at roomtemperature. After 28 h the reaction is complete according to LCMS andis concentrated. The crude material is purified using silica gelchromatography (gradient from 100% dichloromethane to 25% acetone indichloromethane) to yield (6aS)-4′,5′-dihydro-5′toluenesulfonyldeguelinenol ether.

Synthesis of (6aS,12aS)-4′,5′-dihydro-5′[¹⁸F]flourodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100 degreesC. The residue is further dried by repeated addition and evaporation ofCH₃CN (3×200 uL). An additional aliquot of CH₃CN is added andconcentrated under vacuum without heating. Prior to complete solventremoval, THF (150 uL) is added, the vial is uncrimped and(6aS)-4′,5′-dihydro-5′toluenesulfonyldeguelin enol ether (2 mg) is addedin one portion. The vial is recapped and heated at 65 degrees C. for 30minutes. After cooling down to room temperature, a solution oftrifluoroacteic acid (500 μL) and water (300 μL) is slowly added. Thereaction vessel is closed and allowed to stand at 60° C. for 2 min.After cooling to room temperature, the vial is diluted with water (4 mL)and passed through a silica gel cartridge (pre-loaded Waters Light C-18Sep-Pak) to load the sample. The cartridge is rinsed with water andeluted with CH₃CN (2 mL). The acetonitrile is evaporated and the residueis purified via HPLC to afford pure carrier-free(6aS,12aS)-4′,5′-dihydro-5′[18F]flourodeguelin.

Synthesis of (6aS)-4′,5′-dihydro-5′-carbonyldeguelin enol ether

(6aS)-4′,5′-dihydro-5′-hydroxydeguelin enol ether (1.0 g, 2.3 mmol)dissolved in dichloromethane (20 mL) is added to a solution of PCC (0.51g, 2.3 mmol) in dichloromethane (20 mL). After stirring at roomtemperature for 2 h, the reaction is filtered through a pad of celiteand concentrated. The crude material is purified by silica gelchromatography (100% dichloromethane to 30% acetone in dichloromethane)to yield of (6aS)-4′,5′-dihydro-5′-carbonyldeguelin enol ether.

Synthesis of (6aS)-5′-trimethylstannyldeguelin enol ether

To a solution of 2,4,6-triisopropylbenzenesulfonylhydrazide (33.0 g,0.10 mol) in ACN (100 mL) is added(6aS)-4′,5′-dihydro-5′-carbonyldeguelin enol ether (42.4 g, 0.10 mol) of5′-carbonyl deguelin enol ether and 10 mL of concentrated hydrochloricacid. The solution is stirred at room temperature and then cooled to 0°C. for 4 h. The trisyl hydrazone derivative is collected as a solid.

A solution of the trisyl hydrazone derivative (38.3 mmol, 22.67 g) in200 mL of TMEDA-hexanes (1:1) is metalated with exactly 2.0 equivalentsof sec-buytllithium/cyclohexane (76.6 mmole s-BuLi, −80° C.) and allowedto warm to −10° C. until N₂ evolution ceased (40 min.) A solution offreshly sublimed trimethyltin chloride (50 mmole, 9.97 g, 1.3 equiv.) in30 mL hexane is added all at once. Aqueous work-up is followed bydistillation through a short path apparatus at reduced pressure to give(6aS)-5′-trimethylstannyldeguelin enol ether.

Synthesis of (6aS,12aS)-5′[¹⁸F]flourodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100 degreesC. The residue is further dried by repeated addition and evaporation ofCH₃CN (3×200 uL). An additional aliquot of CH₃CN is added andconcentrated under vacuum without heating. Prior to complete solventremoval, THF (150 uL) is added, the vial is uncrimped and(6aS)-5′-trimethylstannyldeguelin enol ether (2 mg) is added in oneportion. The vial is recapped and heated at 65 degrees C. for 30minutes. After cooling down to room temperature, a solution oftrifluoroacteic acid (500 μL) and water (300 μL) is slowly added. Thereaction vessel is closed and allowed to stand at 60° C. for 2 min.After cooling to room temperature, the vial is diluted with water (4 mL)and passed through a silica gel cartridge (pre-loaded Waters Light C-18Sep-Pak) to load the sample. The cartridge is rinsed with water andeluted with CH₃CN (2 mL). The acetonitrile is evaporated and the residueis purified via HPLC to afford pure carrier-free (6aS,12aS)-5′[¹⁸F]flourodeguelin.

Synthesis of (6aS)-4′,5′-dihydro-4′ hydroxydeguelin enol ether

(6aS)-Deguelin enol ether (155.0 mg, 0.38 mmol) and catecholborane (0.40mL of 1.0M THF solution, 0.40 mmol) are added to a solution of catalystA (0.003 g, 1 mol %) in THF (0.5 mL). Catalyst A is prepared accordingto the procedures found in WO 95/13284. The mixture is stirred undernitrogen for 2 h, then quenched with EtOH (0.5 mL), NaOH (2.0 M inwater, 0.5 mL) and hydrogen peroxide (30% in water, 0.5 mL), withstirring for an additional two hours. The reaction mixture is extractedwith diethyl ether. The organic layer is washed with 1.0 M NaOH, driedover Na₂SO₄, and purified using silica gel chromatography (100%dichloromethane to 30% acetone in dichloromethane to yield(6aS)-4′,5′-dihydro-4′ hydroxydeguelin enol ether.

Synthesis of (6aS)-4′,5′-dihydro-4′-carbonyldeguelin enol ether

(6aS)-4′,5′-dihydro-5′-hydroxydeguelin enol ether (1.0 g, 2.3 mmol)dissolved in dichloromethane (20 mL) is added to a solution of PCC (0.51g, 2.3 mmol) in dichloromethane (20 mL). After stirring at roomtemperature for 2 h, the reaction is filtered through a pad of celiteand concentrated. The crude material is purified by silica gelchromatography (100% dichloromethane to 30% acetone in dichloromethane)to yield (6aS)-4′,5′-dihydro-4′-carbonyldeguelin enol ether.

Synthesis of (6aS)-4′-trimethylstannyldeguelin enol ether

To a solution of 2,4,6-triisopropylbenzenesulfonylhydrazide (33.0 g,0.10 mol) in ACN (100 mL) is added(6aS)-4′,5′-dihydro-4′-carbonyldeguelin enol ether (42.4 g, 0.10 mol)and 10 mL of concentrated hydrochloric acid. The solution is stirred atroom temperature and then cooled to 0° C. for 4 h. The trisyl hydrazonederivative is collected as a solid.

A solution of the trisyl hydrazone derivative (38.3 mmol, 22.67 g) in200 mL of TMEDA-hexanes (1:1) is metalated with exactly 2.0 equivalentsof sec-buytllithium/cyclohexane (76.6 mmole s-BuLi, −80° C.) and allowedto warm to −10° C. until N₂ evolution ceased (40 min.) A solution offreshly sublimed trimethyltin chloride (50 mmole, 9.97 g, 1.3 equiv.) in30 mL hexane is added all at once. Aqueous work-up is followed bydistillation through a short path apparatus at reduced pressure to give(6aS)-4′-trimethylstannyldeguelin enol ether.

Synthesis of (6aS,12aS)-4′[¹⁸F]fluorodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100 degreesC. The residue is further dried by repeated addition and evaporation ofCH₃CN (3×200 uL). An additional aliquot of CH₃CN is added andconcentrated under vacuum without heating. Prior to complete solventremoval, THF (150 uL) is added, the vial is uncrimped and(6aS)-5′-trimethylstannyldeguelin enol ether (2 mg) is added in oneportion. The vial is recapped and heated at 65 degrees C. for 30minutes. After cooling down to room temperature, a solution oftrifluoroacteic acid (500 μL) and water (300 μL) is slowly added. Thereaction vessel is closed and allowed to stand at 60° C. for 2 min.After cooling to room temperature, the vial is diluted with water (4 mL)and passed through a silica gel cartridge (pre-loaded Waters Light C-18Sep-Pak) to load the sample. The cartridge is rinsed with water andeluted with CH₃CN (2 mL). The acetonitrile is evaporated and the residueis purified via HPLC to afford pure carrier-free (6aS,12aS)-4′[¹⁸F]flourodeguelin.

Synthesis of 2,4-dihydroxy-6-nitro-benzaldehyde

2,4-dimethoxy-6-nitro-benzaldehyde (135 mg, 0.638 mmol) and sodiummethanethiolate (125 mg, 1.78 mmol) are dissolved in 4 ml ofN,N-dimethylacetamide and heated at 80° C. for 26 h. The reactionmixture is diluted to 50 ml with water and extracted withdichloromethane. The aqueous layer is then acidified with 5% HCl andextracted again with dichloromethane. All of the organic layers aredried over Na₂SO₄, concentrated, and purified using silica gelchromatography (100% dichloromethane to 30% acetone in dichloromethane)to yield 2,4-dihydroxy-6-nitro-benzaldehyde.

Synthesis of 2,4-dihydroxy-5-nitro-benzaldehyde

2,4-dimethoxy-5-nitro-benzaldehyde (135 mg, 0.638 mmol) and sodiummethanethiolate (125 mg, 1.78 mmol) are dissolved in 4 ml ofN,N-dimethylacetamide and heated at 80° C. for 26 h. The reactionmixture is diluted to 50 ml with water and extracted withdichloromethane. The aqueous layer is then acidified with 5% HCl andextracted again with dichloromethane. All of the organic layers aredried over Na₂SO₄, concentrated, and purified using silica gelchromatography (100% dichloromethane to 30% acetone in dichloromethane)to yield 2,4-dihydroxy-5-nitro-benzaldehyde.

Synthesis of 5-hydroxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde

A solution of 2,4-dihydroxy-5-nitro-benzaldehyde (10.61 g, 58 mmol) inMe₂CO (6 mL) is added during a 5.5 h period to a stirring solution of3-methyl-but-2-enal (4.00 g, 29 mmol) in pyridine (2.29 g, 2.34 mL, 29mmol) at 120° C. After completion of addition heating is continued foran additional 18 h. The Me₂CO is evaporated and the pyridine is removedby azeotrope distillation with toluene to afford a crude product. Thecrude product is purified using silica gel chromatography with 1% ethylacetate in hexanes to afford5-hydroxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde.

Synthesis of 5-hydroxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde

A solution of 2,4-dihydroxy-6-nitro-benzaldehyde (10.61 g, 58 mmol) inMe₂CO (6 mL) is added during a 5.5 h period to a stirring solution of3-methyl-but-2-enal (4.00 g, 29 mmol) in pyridine (2.29 g, 2.34 mL, 29mmol) at 120° C. After completion of addition heating is continued foran additional 18 h. The Me₂CO is evaporated and the pyridine is removedby azeotrope distillation with toluene to afford a crude product. Thecrude product is purified using silica gel chromatography with 1% ethylacetate in hexanes to afford5-hydroxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde.

Synthesis of 5-methoxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde

A mixture of 5-hydroxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde(2.34 g, 10 mmol), K₂CO₃ (4.12 g, 29.8 mmol) and MeI (2.13 g, 0.94 mL,15 mmol in Me₂CO (40 mL) is refluxed for 4 h and stirred at roomtemperature overnight. The mixture is concentrated, treated with water(15 mL) and extracted with dichloromethane. The combined organic layersare washed with water, dried over Na₂SO₄, and the solvent is removed invacuo to afford an oil, which is chromatographed with 3% Me₂CO in hexaneto afford 5-methoxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde.

Synthesis of 5-methoxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde

A mixture of 5-hydroxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde(2.34 g, 10 mmol), K₂CO₃ (4.12 g, 29.8 mmol) and MeI (2.13 g, 0.94 mL,15 mmol in Me₂CO (40 mL) is refluxed for 4 h and stirred at roomtemperature overnight. The mixture is concentrated, treated with water(15 mL) and extracted with dichloromethane. The combined organic layersare washed with water, dried over Na₂SO₄, and the solvent is removed invacuo to afford an oil, which is chromatographed with 3% Me₂CO in hexaneto afford 5-methoxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde.

Synthesis of 4-but-2-ynyloxy-1,2-dimethoxybenzene

To 3,4-dimethoxy phenol (15.4 g, 0.1 mol) in DMF (100 mL) is addedpropargyl bromide (14.15 g, 0.12 mol) and potassium carbonate (11.88 g,0.12 mol). The reaction is stirred at room temperature for 12 h, sat.NH₄Cl and diethyl ether are added. The organic layers are washed withwater, brine and dried over Na₂SO₄. The crude material is filteredthrough a pad of silica (1:1 hexanes:dichloromethane) to afford4-but-2-ynyloxy-1,2-dimethoxybenzene as a yellow oil.

Synthesis of4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-but-2-yn-1-one

To a solution of 4-but-2-ynyloxy-1,2-dimethoxybenzene (1.66 g, 8.66mmol) in THF (75 mL) is added n-butyl lithium (5.54 ml of 1.6 M solutionin THF, 8.86 mmol) at −78° C. After 30 min.,5-methoxy-2,2-dimethyl-8-nitro-2H-chromene-6-carbaldehyde (2.17 g, 8.25mmol) in THF (50 mL) is added. The reaction is stirred for 1 h and thenquenched with sat. NH₄Cl and extracted with ethyl acetate. The combinedorganic layers are washed with brine and dried over Na₂SO₄. Theresulting crude material is dissolved in dichloromethane (20 mL) andMnO₂ (5.3 g, 61 mmol) is added. After the reaction is stirred overnightat room temperature, ether is added and the suspension is filteredthrough a pad of celite and silica gel to afford4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-but-2-yn-1-one.

Synthesis of4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-but-2-yn-1-one

To a solution of 4-but-2-ynyloxy-1,2-dimethoxy-benzene (1.66 g, 8.66mmol) in THF (75 mL) is added n-butyl lithium (5.54 ml of 1.6 M solutionin THF, 8.86 mmol) at −78° C. After 30 min.,5-methoxy-2,2-dimethyl-7-nitro-2H-chromene-6-carbaldehyde (2.17 g, 8.25mmol) in THF (50 mL) is added. The reaction is stirred for 1 h and thenquenched with sat. NH₄Cl and extracted with ethyl acetate. The combinedorganic layers are washed with brine and dried over Na₂SO₄. Theresulting crude material is dissolved in dichloromethane (20 mL) andMnO₂ (5.3 g, 61 mmol) is added. After the reaction is stirred overnightat room temperature, ether is added and the suspension is filteredthrough a pad of celite and silica gel to afford4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-but-2-yn-1-one.

Synthesis of(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-methanone

In a flame dried 10 ml round bottom flask is added4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-but-2-yn-1-one(61.6 mg, 0.135 mmol) and PtCl₂ (1.8 mg, 5 mol %). The flask isevacuated and flushed with argon three times, followed by the additionof toluene (1.8 mL, 0.1 m). The reaction is allowed to stir at 55° C.for 10 h and then concentrated. The crude material is purified usingsilica gel chromatography (7:3 hexanes:ethyl acetate) to

afford(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-methanone.

Synthesis of(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-methanone

In a flame dried 10 ml round bottom flask is added4-(3,4-dimethoxy-phenyoxy)-1-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-but-2-yn-1-one(61.6 mg, 0.135 mmol) and PtCl₂ (1.8 mg, 5 mol %). The flask isevacuated and flushed with argon three times, followed by the additionof toluene (1.8 mL, 0.1 m). The reaction is allowed to stir at 55° C.for 10 h and then concentrated. The crude material is purified usingsilica gel chromatography (7:3 hexanes:ethyl acetate) to afford(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-methanone.

Synthesis of (+/−)-10-nitrodeguelin

To a flame dried 10 mL round bottom flask is added(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-8-nitro-2H-chromen-6-yl)-methanone(50.2 mg, 0.111 mmol) and dichloromethane (2.0 mL). The solution iscooled to −78° C. and boron trichloride (0.133 mL, 1 M solution indichloromethane, 0.133 mmol) is added. After stirring for 1 h thereaction is quenched with sat. NH₄Cl, extracted with

ethyl acetate, dried over Na₂SO₄, and concentrated. The crude materialis dissolved in EtOH, saturated with potassium acetate and refluxed for1 h. After cooling down to room temperature, ethyl acetate and water areadded to the reaction mixture. The aqueous layer is extracted with ethylacetate. Combined organic layers are washed

with brine, dried over Na₂SO₄, and concentrated. The crude material isfiltered through a pad of silica (3:1 hexanes, ethyl acetate) to yield(+/−)-10-nitrodeguelin.

Synthesis of (+/−)11-nitrodeguelin

To a flame dried 10 mL round bottom flask is added(6,7-dimethoxy-2H-chroman-3-yl)-(5-methoxy-2,2-dimethyl-7-nitro-2H-chromen-6-yl)-methanone(50.2 mg, 0.111 mmol) and dichloromethane (2.0 mL). The solution iscooled to −78° C. and boron trichloride (0.133 mL, 1 M solution indichloromethane, 0.133 mmol) is added. After stirring for 1 h thereaction is quenched with sat. NH₄Cl, extracted with ethyl acetate,dried over Na₂SO₄, and concentrated. The crude material is dissolved inEtOH, saturated with potassium acetate and refluxed for 1 h. Aftercooling down to room temperature, ethyl acetate and water are added tothe reaction mixture. The aqueous layer is extracted with ethyl acetate.Combined organic layers are washed with brine, dried over Na₂SO₄, andconcentrated. The crude material is filtered through a pad of silica(3:1 hexanes, ethyl acetate) to yield (+/−)-11-nitrodeguelin.

Synthesis of (+/−)-11-[¹⁸F]fluorodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to

dryness under a flow of nitrogen at 100° C. The residue is further driedby repeated addition and evaporation of CH₃CN (3×200 uL). An additionalaliquot of CH₃CN is added and concentrated under vacuum without heating.Prior to complete solvent removal, THF (150 uL) is added, the vial isuncrimped and (+/−)-11-nitrodeguelin (2 mg) is added in one portion. Thevial is recapped and heated at 65° C. for 30 minutes. After cooling toroom temperature, the vial is diluted with water (4 mL) and passedthrough a silica gel cartridge (pre-loaded Waters Light C-18 Sep-Pak) toload the sample. The cartridge is rinsed with water and eluted withCH₃CN (2 mL). The acetonitrile is evaporated and the residue is purifiedvia HPLC to afford pure carrier-free (+/−)-11-[¹⁸F]fluorodeguelin

Synthesis of (+/−)-10-[¹⁸F]fluorodeguelin

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and (+/−)-10-nitrodeguelin (2mg) is added in one portion. The vial is recapped and heated at 65° C.for 30 minutes. After cooling to room temperature, the vial is dilutedwith water (4 mL) and passed through a silica gel cartridge (pre-loadedWaters Light C-18 Sep-Pak) to load the sample. The cartridge is rinsedwith water and eluted with CH₃CN (2 mL). The acetonitrile is evaporatedand the residue is purified via HPLC to afford pure carrier-free(+/−)-10-[¹⁸F]fluorodeguelin.

Example 2 Tebufenpyrad Analogs Synthesis5-N-(4-tert-butylbenzyl)carboxamido-3-(methoxycarbonyl)-1-methylpyrazole

A mixture of 3-(methoxycarbonyl)-1-methyl-5-carboxylic acid (20 mmole)and thionyl chloride (30 mmole) is heated at reflux for 30 minutes. Theexcess thionyl chloride is removed under vacuum, and the residue driedvia azeotrope with dry benzene. The resultant crude acyl chloride isdissolved in THF (10 mL) and stirred while cooling at 0 degrees C. whilea solution of 4-tert-butylbenzylamine (22 mmole) anddiisopropylethylamine (25 mmole) in THF (5 mL) is added dropwise. Thereaction mixture is stirred at room temperature for 1 hour, and heatedto reflux briefly to complete the reaction. The mixture is cooled andpoured into ice-cold water (100 mL) and is extracted with ether (3×100mL). The combined organics are dried (sat'd aq. NaCl, Na₂SO₄), filteredand concentrated. Purification of the residue via flash columnchromatography (silica gel, gradient elution with 0-20% ethylacetate/hexanes) affords5-N-(4-tert-butylbenzyl)carboxamido-3-(methoxycarbonyl)-1-methylpyrazole.

Synthesis of Methyl 5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1methyl-3-pyrazolylcarboxylate

A solution of5-N-(4-tert-butylbenzyl)carboxamido-3-(methoxycarbonyl)-1-methylpyrazole(0.1 mole) and thionyl chloride (0.13 mole) in 1,2-dichloroethane (15mL) is heated at reflux for two hours. The reaction mixture is cooledand concentrated in vacuo. The residue is partitioned betweendichloromethane (100 mL) and sat'd aq. NaHCO₃ (100 mL), ensuring the pHof the aqueous phase is >7. The aqueous layer is separated and extractedwith dichloromethane (2×100 mL), and the combined organics are dried(sat'd aq. NaCl, Na₂SO₄), filtered and concentrated. Recrystallizationof the residue (EtOH-water) affords pure methyl5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolylcarboxylate.

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolylcarboxylic acid

A solution of methyl5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolylcarboxylate(50 mmole) in dioxane (33 mL) and water (75 mL) is treated with asolution of H₂SO₄ (conc., 1 mL) in water (1.5 mL). The resultant mixtureis heated at reflux to exhaustion of the starting material. Theresultant mixture is concentrated in vacuo to the saturation point(removal of the dioxane), and cooled at 0° C. overnight. The resultantprecipitate is collected by filtration and dried. The filtrate isextracted with dichloromethane (3×100 mL) and the combined organics aredried (sat'd aq. NaCl, Na₂SO₄), filtered and concentrated.Recrystallization of the residue (ethyl acetate-methanol) affords pure5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolylcarboxylic acid.

Synthesis of1-(5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolyl)-1-ethanone

A solution of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolylcarboxylic acid (20 mmole) in thionyl chloride (30 mmole) is heated atreflux for 15 minutes. The mixture is cooled and concentrated in vacuo.Benzene (10 mL) is added, and removed first at atmospheric pressure,then under vacuum. The resultant acid chloride is used directly in thenext step.

A flask is charged with solid anhydrous cuprous bromide (25 mmole), andflushed with argon. Tetrahydrofuran (125 mL) is added. The resultantsuspension is cooled at −78° C. while a solution of methylmagnesiumbromide (17.8 mL, 2.9M in diethyl ether) is added dropwise. The mixtureis stirred while cooling at −78° C. for 20 minutes. The above preparedacid chloride is dissolved in THF (10 mL) and cooled to −78° C. The acidchloride is slowly added to the cuprate via cannula, allowing theaddition solution to run down the side of the reaction flask forre-cooling. The acid chloride flask is rinsed with THF (5 mL), which isagain cooled and added via cannula. The bath is removed and the mixtureis stirred at room temperature for 30 minutes. Methanol (4 mL) is addedto quench the reaction, and the mixture is poured into saturated aqueousNH₄Cl (200 mL). The mixture is stirred for one hour to dissolve thecopper salts and the organic layer is separated. The aqueous phase iswashed with dichloromethane (2×200 mL) and the combined organics aredried (sat'd aq. NaCl, Na₂SO₄), filtered and concentrated. The residueis purified via chromatography (silica gel, gradient elution 10-30%ethyl acetate-hexanes) to afford pure1-(5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolyl)-1-ethanone.

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-3-(1-hydroxyethyl)-1-methylpyrazoline

Sodium borohydride (20 mmole) is added as a solid in one portion to astirred solution of1-(5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-pyrazolyl)1-ethanone (10 mmole) in ethanol (15 mL) at room temperature. Themixture is stirred to exhaustion of the starting ketone. More sodiumborohydride is added if necessary. Water (2 mL) is added, the mixtureconcentrated and the mixture is partitioned between water (100 mL) anddichloromethane (2×100 mL). The combined organics are dried (sat'd aq.NaCl, Na₂SO₄), filtered and concentrated. The residue is purified viachromatography (silica gel, gradient elution. 10-30% ethylacetate-hexanes) to afford pure 5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-3-(1-hydroxyethyl)-1-methylpyrazoline.

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-p-toluenesulfonatoethyl)pyrazoline

A solution of 5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-3-(1-hydroxyethyl)-1-methylpyrazoline (5 mmole) andp-toluenesulfonyl chloride (5.5 mmole) in pyridine (12 mL) is stirred atroom temperature for four hours. The solution is concentrated and ispartitioned between water (100 mL) and dichloromethane (2×100 mL). Thecombined organics are dried (sat'd aq. NaCl, Na₂SO₄), filtered andconcentrated. The residue is purified via chromatography (silica gel,gradient elution 2-20% ethyl acetate-hexanes) to afford pure5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-p-toluenesulfonatoethyl)pyrazoline.

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-[¹⁸F]fluoroethyl)pyrazoline(via tosylate)

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and pure5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-p-toluenesulfonatoethyl)pyrazoline(2 mg) is added in one portion as a solid. The vial is recapped andheated at 65° C. for 30 minutes. After cooling, the vial is diluted withwater (4 mL) and passed through a silica gel cartridge (pre-loadedWaters Light C-18 Sep-Pak) to load the sample. The cartridge is rinsedwith water and eluted with CH₃CN (2 mL). The acetonitrile is evaporatedand the residue is purified via HPLC to afford pure carrier-free5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-[¹⁸F]fluoroethyl)pyrazoline

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-methanesulfonatoethyl)pyrazoline

A solution of 5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-3-(1-hydroxyethyl)-1-methylpyrazoline (5 mmole) andmethanesulfonyl chloride (5.5 mmole) in pyridine (12 mL) is stirred atroom temperature for four hours. The solution is concentrated and ispartitioned between water (100 mL) and dichloromethane (2×100 mL). Thecombined organics are dried (sat'd aq. NaCl, Na₂SO₄), filtered andconcentrated. The residue is purified via chromatography (silica gel,gradient elution 2-20% ethyl acetate-hexanes) to afford pure5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-methanesulfonatoethyl)pyrazoline.

Synthesis of5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-[¹⁸F]fluoroethyl)pyrazoline(via mesylate)

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, THF(150 uL) is added, the vial is uncrimped and pure5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-methanesulfonatoethyl)pyrazoline(2 mg) is added in one portion as a solid. The vial is recapped andheated at 65 degrees C. for 30 minutes. After cooling, the vial isdiluted with water (4 mL) and passed through a silica gel cartridge(pre-loaded Waters Light C-18 Sep-Pak) to load the sample. The cartridgeis rinsed with water and eluted with CH₃CN (2 mL). The acetonitrile isevaporated and the residue is purified via HPLC to afford purecarrier-free5-N-(4-tert-butyl)benzylcarboxamido-4-chloro-1-methyl-3-(1-[¹⁸F]fluoroethyl)pyrazoline

Synthesis of 4-tert-butyl-3-nitrobenzamide

A mixture of 4-tert-butyl-3-nitrobenzoic acid (0.1 mole),hydroxybenzotriazole (HOBt, 0.12 mole) and dicyclohexylcarbodiimide(DCC, 0.11 mole) in dichloromethane (100 mL) is stirred at roomtemperature while a solution of ammonia in 2-propanol (2.0M, 75 mL, 0.12mole) is added rapidly. The mixture is stirred for two hours at roomtemperature, and poured into aqueous NaHCO₃ (5%, 200 mL). The layers areseparated, and the aqueous phase is extracted with dichloromethane(2×200 mL). The combined organics are washed (2×200 mL 5% aq. NaHCO₃),dried (sat'd aq. NaCl, Na₂SO₄), filtered and concentrated. The productis recrystallized from EtOH-water to afford pure4-tert-butyl-3-nitrobenzamide.

Synthesis of 4-tert-butyl-3-[¹⁸F]fluorobenzylamine

A thin-wall 10 mL, silanized vacutainer with a silanized stopper ischarged with tetrabutyl ammonium hydroxide (5 uL, 40% w/v solution inwater), and a solution of ¹⁸F⁻ in water (10 mCi, 200 uL). The resultantmixture is evaporated to dryness under a flow of nitrogen at 100° C. Theresidue is further dried by repeated addition and evaporation of CH₃CN(3×200 uL). An additional aliquot of CH₃CN is added and concentratedunder vacuum without heating. Prior to complete solvent removal, dioxane(150 uL) is added, the vial is uncrimped and4-tert-butyl-3-nitrobenzamide (1 mg, ca. 4.5 umoles) is added in oneportion as a solid. The vial is recapped and heated at 100° C. for 25minutes. After cooling, a solution of lithium aluminum hydridebis(tetrahydrofuran) in toluene (1.0M, 50 uL, 50 umoles) is added, andthe mixture is heated at 50 degrees C. for five minutes. The vial iscooled and the contents are diluted with water (4 mL) and passed througha silica gel cartridge (pre-loaded Waters Light C-18 Sep-Pak) to loadthe sample. The cartridge is rinsed with water and eluted with CH₃CN (2mL). The acetonitrile is evaporated and the residue is purified via HPLCto afford pure carrier-free 4-tert-butyl-3-[¹⁸F]fluorobenzylamine. Thesolvent is evaporated and the material is used directly in the followingprocedure.

Synthesis of5-N-(4-tert-butyl-3-[¹⁸F]fluoro)benzylcarboxamido-4-chloro-3-ethyl-1-methylpyrazoline

To a stirred mixture of 3-ethyl-1-methylpyrazole-5-carboxylic acid (50umole), dicyclohexylcarbodiimide (DCC, 50 umole, delivered as an aliquotfrom a stock solution in dichloromethane), hydroxybenzotriazole (HOBt,60 umole) in methylene chloride (200 uL), is added a solution of4-tert-butyl-3-[¹⁸F]fluorobenzylamine (prepared above) indichloromethane (100 uL). The mixture is stirred at room temperature forten minutes at room temperature, concentrated and dissolved inacetonitrile-water (1:4, 3 mL). The mixture is passed through a silicagel cartridge (pre-loaded Waters Light C-18 Sep-Pak) to load the sample.The cartridge is rinsed with water and eluted with CH₃CN (2 mL). Theacetonitrile is evaporated and the residue is purified via HPLC toafford pure carrier-free5-N-(4-tert-butyl-3-[¹⁸F]fluoro)benzylcarboxamido-4-chloro-3-ethyl-1-methylpyrazoline.

Example 3 Pyridaben Analogs Synthesis of2-tert-butyl-4,5-dichloro-3(2H)-pyridazinone

To mucochloric acid (4.0 g, 23.6 mmol) in water (35 ml) at 0° C. wasadded anhydrous Na₂CO₃ (1.21 g, 11.5 mmol). This was stirred till aclear solution was obtained and to this was added tert-butylhydrazinehydrochloride (2.94 g, 23.6 mmol). A precipitate started to form after afew minutes. The reaction was stirred for a further 2.5 hrs after whichit was filtered. The yellow precipitate was washed with cold water anddried to give 4.81 g of the crude hydrazone.

To 4.32 g of the crude hydrazone was added 40 ml of acetic acid and thesolution was refluxed for 25 minutes. The solution was then cooled andconcentrated. This was then taken up in dichloromethane and washed with1M sodium carbonate and water. The organic layer was then dried andconcentrated to give a yellow solid which was purified by columnchromatography using hexanes:chloroform (1:1 to 0:100) as the elutingsolvent. This afforded 2.4 g of the above as a white solid.

Synthesis of 2-tert-Butyl-4-chloro-5-thio-3(2H)-pyridazinone

To 0.5 g of 2-tert-Butyl-4,5-dichloro-3(2H)-pyridazinone was added 7 mlwater and sodium sulfide (0.53 g, 6.81 mmol) and the mixture was heatedto 80° C. until all the solid dissolved. The solution was then cooled toroom temperature and concentrated HCl was carefully added to give ayellow precipitate, which was filtered and washed with cold water.Crystallization from hexanes afforded the product as a white solid (270mg).

Synthesis of 2-tert-butyl-4-chloro-5-(4-tert-butylbenzyl)thio3(2H)-pyridazinone

To 220 mg of 2-tert-butyl-4-chloro-5-thio-3(2H)-pyridazinone in 4 ml DMFwas added 4-tert-butylbenzyl bromide (226 mg, 1 mmol) and Na₂CO₃. Thereaction mixture was stirred for 16 hrs at room temperature after whichit was extracted in ethyl acetate, washed with water and purified bycolumn chromatography (silica gel; ethyl acetate/hexanes) as the eluent.This afforded the above mentioned compound.

Synthesis of 2-tert-butyl-4-fluoro-5-(4-tert-butylbenzyl)thio3(2H)-pyridazinone

A round bottom flask is charged with2-tert-butyl-4-chloro-5-(4-tert-butylbenzyl)thio 3(2H)-pyridazinone (100mg, 0.27 mmol) and to it is added potassium fluoride (23.4 mg, 0.40mmol) and 2 ml dimethyl sulfoxide. This is heated to 120° C. for 6hours. The reaction mixture is then poured into water and extracted withethyl acetate. This is washed with water and dried. Purification byflash chromatography (silica gel; ethyl acetate/hexanes) gave the abovementioned compound.

Synthesis of 2-tert-butyl-4-[¹⁸F]fluoro-5-(4-tert-butylbenzyl)thio3(2H)-pyridazinone

To a 5 ml reaction vial containing 500 mCi of ¹⁸F in 350 mg of ¹⁸O wateris added a 1 ml solution consisting of 10 mg of Kryptofix, 1 mgpotassium carbonate, 0.005 ml water and 0.95 ml acetonitrile. The vialis heated to remove all the solvents and dry acetonitrile (1 ml) isadded to the vial. This is also removed by evaporation.2-tert-butyl-4-chloro-5-(4-tert-butylbenzyl)thio 3(2H)-pyridazinone (5mg) in acetonitrile is then added to it. The vial is sealed and heatedfor 30 minutes at 100° C. The mixture is diluted with dichloromethaneand passed through a Sep-Pak and eluted with tetrahydrofuran. Thesolvent is evaporated to get the above mentioned compound.

Synthesis of 4-(4-Methylphenyl)butanol

To lithium aluminum hydride (427 mg, 11.2 mmol) suspended in dry ether(5 ml) at 0° C. is added 1 g of 4-(4-methylphenyl)butanoic acid (5.614mmol) dissolved in dry ether (10 ml) over a period of 30 minutes. Thereaction mixture is then warmed to room temperature and stirred for 4hours. Water (0.43 ml), NaOH (15% solution, 0.43 g) and water (1.29 ml)are then added successively and the resulting solution is stirred for 30minutes. The precipitate is filtered and washed with ether and dried.This is then concentrated and purified by flash chromatography (silicagel; ethyl acetate/hexanes) as the eluting medium.

Synthesis of 4-(4-methylphenyl)-butyl tert-butyldimethylsilyl ether

4-(4-Methylphenyl)butanol (0.5 g, 3.04 mmol) is dissolved in 5 ml DMFand to it is added imidazole (310 mg, 4.56 mmol) andtert-butyldimethylsilyl chloride (685 mg, 4.56 mmol). The reaction isstirred for 4 hrs after which it is extracted in ethyl acetate andwashed with water to remove all DMF. The organic layer is then dried andconcentrated. The crude mixture is then purified by flash chromatographyusing a mixture of ethyl acetate-hexanes as the eluting medium to affordthe above mentioned product.

Synthesis of 4-(4-bromomethylphenyl)butyl tert-butyldimethylsilyl ether

To a 50 ml round bottom flask is added 4-(4-methylphenyl)butyltert-butyldimethylsilyl ether (0.25 g, 0.89 mmol), N-bromosuccinimide(0.158 g, 0.89 mmol), benzoyl peroxide (2.17 mg, 0.0089 mmol) and 10 mlcarbon tetrachloride. This mixture is refluxed overnight after which itis cooled and filtered. The filtrate is concentrated and the resultingcrude residue is purified by flash chromatography in ethylacetate-hexanes to afford the product.

Synthesis of 2-tert-butyl-4-chloro-5-(4-(4-tert-butyldimethylsilyloxybutyl)benzyl)thio-3(2H)-pyridazinone

To a flask containing 2-tert-butyl-4-chloro-5-thio-3(2H)-pyridazinone(0.2 g, 0.917 mmol) is added 5 ml DMF followed by cesium carbonate(0.358 g, 1.1 mmol) and 4-(4-bromomethylphenyl)-butyltert-butyldimethylsilyl ether (0.391 g, 1.1 mmol). The mixture is heatedto 60° C. for 2 hrs after which it is cooled, extracted in ethylacetate, washed, dried and concentrated. The crude mixture is thenpurified by chromatography using silica gel and a mixture of ethylacetate—hexanes as the eluent. This affords the above mentioned product.

Synthesis of2-tert-butyl-4-chloro-5-(4-(4-hydroxybutyl)benzyl)thio-3(2H)pyridazinone

To 0.2 g 2-tert-butyl-4-chloro-5-(4-(4-tert-butyldimethylsilyloxybutyl)benzyl)thio-3(2H)-pyridazinone (0.404 mmol) is added 5 ml of 1%concd. HCl

in ethanol. The reaction mixture is stirred for 30 minutes after whichit is extracted in ethyl acetate, washed with water and dried.Purification (silica gel; EtOAC/hexanes) of the crude mixture obtainedafter concentration yields the desired product

Synthesis of2-tert-butyl-4-chloro-5-(4-(4-toluenesulfonyloxybutyl)benzyl)thio-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-chloro-5-(4-(4-hydroxybutyl)benzyl)thio-3(2H)-pyridazinone(0.15 g, 0.39 mmol) is added pyridine. Toluenesulfonyl chloride (88.9mg, 0.42 mmol) is then added to it and the mixture stirred for 2 hours.The reaction mixture is diluted with ethyl acetate, washed with 5%copper sulfate solution and then with water and dried. After removingthe solvent on the rotary evaporator the crude is purified by flashchromatography using ethyl acetate—hexanes as the eluting mixture.

Synthesis of2-tert-butyl-4-chloro-5-(4-(4-fluorobutyl)benzyl)thio-3(2H)-pyridazinone

To a round bottom flask is added2-tert-butyl-4-chloro-5-(4-(4-toluenesulfonyloxybutyl)benzyl)thio-3(2H)-pyridazinone(0.05 g, 0.093 mmol) and to it is added tetrabutylammonium fluoride (1.0M solution in THF, 0.93 μl, 0.93 mmol) followed by 0.2 ml of THF. Thereaction is heated to 60 C and stirred at that temperature for 30minutes. The mixture is then cooled and concentrated and the crudesubjected to flash chromatography to obtain the above mention compound.

Synthesis of2-tert-butyl-4-chloro-5-(4-(4-[¹⁸F]-fluorobutyl)benzyl)thio-3(2H)-pyridazinone

Aqueous ¹⁸F (16 mCi, 0.1 ml) is added to a vacutainer containing 5 μl oftetrabutylammonium hydroxide (40% wt sol. in water). The mixture isconcentrated under nitrogen in an oil bath and 250 μl of acetonitrile isadded and this too is concentrated under nitrogen. 100 μl of THF is thenadded to it followed by 5 mg of2-tert-butyl-4-chloro-5-(4-(4-toluenesulfonyloxybutyl)benzyl)thio-3(2H)-pyridazinone.The mixture is then heated in an oil bath at 70° C. for 30 minutes. Thisis then diluted with water, applied to a C18 Sep-Pak and eluted withacetonitrile to get the above mentioned compound.

Synthesis of (4-tert-butylphenyl)ethane 1,2 diol

To a 100 ml round bottom flask is added 20 ml tert butanol, 20 ml ofwater and 5.6 g of AD-mix-β. The solution is stirred and cooled to 0 C.tert-butyl styrene (0.64 g, 4 mmol) is added to the mixture and theresulting solution is stirred overnight at 0 C. Solid sodium sulfite (6g) is added and the mixture stirred for an additional 30 minutes. Thesolution is then extracted in ethyl acetate, washed with water anddried. The crude is then purified by flash chromatography (silica gel;ethyl acetate/hexanes) to afford the product.

Synthesis of1-tert-butyldimethylsilyloxy-2-hydroxy-2-(4-tertbutylphenyl)ethane

(4-tert-butylphenyl)ethane 1,2 diol (0.5 g, 2.57 mmol) is dissolved inDMF in a 25 ml round bottom flask and to this were added imidazole(0.210 g, 3.09 mmol) and tert-butyldimethylsilyl chloride (0.46 g, 3.09mmol). The mixture is stirred for 6 hours after which it is extracted indichloromethane and the organic layer washed with water and dried.Purification by flash chromatography (silica gel; ethyl acetate/hexanes)affords the above mentioned product.

Synthesis of2-tert-butyl-4-chloro-5-(2-tert-butyldimethylsilyloxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone

To a solution of 2-tert-butyl-4,5-dichloro-3(2H)-pyridazinone (0.5 g,2.27 mmol) in DMF (10 ml) were added anhydrous cesium carbonate (0.74 g,2.27 mmol) and 1-tert-butyldimethylsilyloxy 2-hydroxy2-(4-tertbutylphenyl)ethane (0.7 g, 2.27 mmol). The mixture is stirredfor 2 hours at 70° C. and then cooled to room temperature and ethylacetate is added to it. The solution is then washed with water, driedand concentrated and the residue subjected to purification by flashchromatography (silica gel; ethyl acetate/hexanes) to give the abovecompound.

Synthesis of2-tert-butyl-4-chloro-5-(2-hydroxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone

A 25 ml round bottom flask is charged2-tert-butyl-4-chloro-5-(2-tert-butyldimethylsilyloxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone(0.5 g, 1.01 mmol) and to it is added 5 ml of 1% concd. HCl in ethanol.The solution is stirred for one hour after which it is poured in waterand extracted with ethyl acetate. The ethyl acetate is removed using therotary evaporator and subjected to flash chromatography using silica geland ethyl acetate/hexanes mixture as the eluting medium.

Synthesis of2-tert-butyl-4-chloro-5-(2-p-toluenesulfonyloxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-chloro-5-(2-hydroxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone(0.25 g, 0.66 mmol) is added pyridine. Toluenesulfonyl chloride (0.15 g,0.79 mmol) is then added to it and the mixture stirred for 4 hours. Thereaction mixture is diluted with ethyl acetate, washed with 5% coppersulfate solution and then with water and dried. After removing thesolvent on the rotary evaporator the crude is purified by flashchromatography using ethyl acetate—hexanes as the eluting mixture.

Synthesis of2-tert-butyl-4-chloro-5-(2-fluoro-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-chloro-5-(2-p-toluenesulfonyloxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone(0.2 g, 0.375 mmol) is added 3.75 ml of tetrabutylammonium fluoridesolution (1M in THF, 3.75 mmol). The mixture is first stirred at roomtemperature for 15 minutes after which it is heated for 15 minutes at100° C. The solution is then cooled to room temperature and to it isadded dichloromethane followed by water. The layers were separated andthe organic layer is washed with water and then dried. The organic layeris then concentrated and subjected to purification using silica gelflash chromatography (ethyl acetate/hexanes) to obtain the abovecompound.

Synthesis of2-tert-butyl-4-chloro-5-(2-[¹⁸F]-fluoro-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone

Aqueous ¹⁸F (16 mCi, 0.1 ml) is added to a vacutainer containing 5 μl oftetrabutylammonium hydroxide (40% wt sol. in water). The mixture isconcentrated under nitrogen in an oil bath and 250 μl of acetonitrile isadded and this too is concentrated under nitrogen. 100 μl of THF is thenadded to it followed by 5 mg of2-tert-butyl-4-chloro-5-(2-p-toluenesulfonyloxy-1-(4-tert-butylphenyl)-1-ethyl)oxy-3(2H)-pyridazinone.The mixture is then heated in an oil bath at 70° C. for 30 minutes. Thisis then diluted with water, applied to a C18 Sep-Pak and eluted withacetonitrile to get the above mentioned compound.

Synthesis of 2-tert-butyl-4-methyl-5-chloro 3(2H)-pyridazinone

2-tert-butyl-4,5-dichloro-3(2H)-pyridazinone (5 g, 22.72 mmol) dissolvedin 12 ml of ether was added dropwise to 15 ml of a ether solution ofmethylmagnesium bromide (3M in ether) at 5° C. was added. Aftercompletion of addition the solution was stirred at 5° C. for 2 hours. 10ml of 6N HCl solution is then added slowly to it and the solution isstirred for 10 minutes. The mixture is then extracted with diethylether. The ether layer is then washed with water and dried. The crudeproduct obtained after concentrating the ether is subjected to flashchromatography (silica gel; ethyl acetate/hexanes: 9:1) to give theproduct.

Synthesis of 2-tert-butyl-4-bromomethyl-5-chloro 3(2H)-pyridazinone

2-tert-butyl-4-methyl-5-chloro 3(2H)-pyridazinone (3 g, 15 mmol) isdissolved in 25 ml of carbon tetrachloride and to it is addedN-bromosuccinimide (2.6 g, 15 mmol) and benzoyl peroxide (14 mg). Themixture is then refluxed for 6 hours after which it is cooled andfiltered. The filtrate is washed with water and dried. After removingthe organic solvent the crude residue obtained is purified by flashchromatography (silica gel; ethyl acetate/hexanes: 9:1) to obtain theproduct.

Synthesis of 2-tert-butyl-4-hydroxymethyl-5-chloro 3(2H)-pyridazinone

2-tert-butyl-4-bromomethyl-5-chloro 3(2H)-pyridazinone (2 g, 7.19 mmol)and calcium carbonate (3.5 gm) are added to a 1:1 mixture ofdioxane—water (40 ml). The mixture is refluxed for 6 hours after which30 ml of 3N HCl solution is added to it. The solution is stirred for 10minutes after which dioxane is removed under reduced pressure. Theresulting solution is then extracted with dichloromethane and thedichloromethane layer is washed and dried. The crude obtained afterconcentration is purified by flash chromatography (ethylacetate/hexanes: 1:2).

Synthesis of 2-tert-butyl-4-tert-butyldimethylsilyloxymethyl-5-chloro3(2H)-pyridazinone

2-tert-butyl-4-hydroxymethyl-5-chloro 3(2H)-pyridazinone (1 g, 4.62mmol) is dissolved in DMF in a 25 ml round bottom flask and to this wereadded imidazole (0.377 g, 5.0 mmol) and tert-butyldimethylsilyl chloride(0.762 g, 3.09 mmol). The mixture is stirred for 10 hours after which itis extracted in dichloromethane and the organic layer washed with waterand dried. Purification by flash chromatography (silica gel; ethylacetate/hexanes) affords the above mentioned product.

Synthesis of2-tert-butyl-4-tert-butyldimethylsilyloxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone

To a solution of2-tert-butyl-4-tert-butyldimethylsilyloxymethyl-5-chloro3(2H)-pyridazinone (1.5 g, 4.54 mmol) in DMF (10 ml) is added anhydrouscesium carbonate (2.9 g, 9.09 mmol) and 4-tert-butylbenzyl mercaptan(1.02 g, 4.54 mmol). The mixture is stirred for 2 hours at 70° C. andthen cooled to room temperature and ethyl acetate is added to it. Thesolution is then washed with water, dried and concentrated and theresidue subjected to purification by flash chromatography (silica gel;ethyl acetate/hexanes) to give the above compound.

Synthesis of2-tert-butyl-4-hydroxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-tert-butyldimethylsilyloxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone(2 g, 4.2 mmol) is added tetrabutylammonium fluoride solution (1M inTHF, 21 ml, 21 mmol). The mixture is first stirred at room temperaturefor 5 hours and to it is added dichloromethane followed by water. Thelayers are separated and the organic layer is washed with water anddried. The organic layer is then concentrated and subjected topurification using silica gel flash chromatography (ethylacetate/hexanes) to obtain the above compound.

Synthesis of2-tert-butyl-4-p-toluenesulfonyloxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-hydroxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone(1.0 g, 2.77 mmol) is added pyridine. p-Toluenesulfonyl chloride (0.79g, 4.15 mmol) is then added to it and the mixture stirred for 4 hours.The reaction mixture is diluted with ethyl acetate, washed with 5%copper sulfate solution and then with water and dried. After removingthe solvent on the rotary evaporator the crude is purified by flashchromatography using (silica gel; ethyl acetate/hexanes) as the elutingmixture to give the product.

Synthesis of2-tert-butyl-4-fluoromethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone

To a 15 ml round bottom flask charged with2-tert-butyl-4-p-toluenesulfonyloxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone(0.5 g, 0.972 mmol) is added 4.86 ml of tetrabutylammonium fluoridesolution (1M in THF, 4.86 mmol). The mixture is first stirred at roomtemperature for 15 minutes after which it is heated for 15 minutes at100° C. The solution is then cooled to room temperature and to it isadded dichloromethane followed by water. The layers were separated andthe organic layer is washed with water and then dried. The organic layeris then concentrated and subjected to purification using silica gelflash chromatography (ethyl acetate/hexanes) to obtain the abovecompound.

Synthesis of2-tert-butyl-4-[¹⁸F]fluoromethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone

Aqueous ¹⁸F (50 mCi, 0.1 ml) is added to a vacutainer containing 5 μl oftetrabutylammonium hydroxide (40% wt sol. in water). The mixture isconcentrated under nitrogen in an oil bath and 250 μl of acetonitrile isadded and this too is concentrated under nitrogen. 100 μl of THF is thenadded to it followed by 5 mg of2-tert-butyl-4-p-toluenesulfonyloxymethyl-5-(4-tert-butylbenzyl)thio-3(2H)-pyridazinone.The mixture is then heated in an oil bath at 70° C. for 30 minutes. Thisis then diluted with water, applied to a C18 Sep-Pak and eluted withacetonitrile to get the above mentioned compound.

Example 4 Fenazaquin Analogs Synthesis of 4-Chloro quinazoline

4-Quinazolone (5 g, 34.2 mmol), phosphorus pentachloride (10.26 g, 47.9mmol) and phosphorus oxychloride (40 ml) were refluxed for two hours at115-118 C. The phosphorus oxychloride was removed in vacuo and theresidue was extracted in ether. The entire mixture was then poured intoa vessel containing crushed ice and again extracted with ether. Theether layer was then washed with sodium bicarbonate and dried. The etherwas then removed under reduced pressure and the crude material wasrecrystallized from hexanes to afford the product.

Synthesis of 4-(4-Methylphenyl)butanol

To lithium aluminum hydride (427 mg, 11.2 mmol) suspended in dry ether(5 ml) at 0° C. is added 1 g of 4-(4-methylphenyl)butanoic acid (5.614mmol) dissolved in dry ether (10 ml) over a period of 30 minutes. Thereaction mixture is then allowed to warm to room temperature and stirredfor 4 hours. Water (0.43 ml), NaOH (15% solution, 0.43 g) and water(1.29 ml) were then added successively and the resulting solution isstirred for 30 minutes. The resulting precipitate is filtered and washedwith ether and dried. The filtrate is then concentrated and purified byflash chromatography using ethyl acetate—hexanes as the eluting medium.

Synthesis of 4-(4-methylphenyl)butyl tert-butyldimethylsilyl ether

4-(4-Methylphenyl)butanol (0.5 g, 3.04 mmol) is dissolved in 5 ml DMFand to it is added imidazole (310 mg, 4.56 mmol) andtert-butyldimethylsilyl chloride (685 mg, 4.56 mmol). The reaction isstirred for 4 hrs after which it is extracted in ethyl acetate andwashed with water to remove all DMF. The organic layer is then dried andconcentrated. The crude mixture is then purified by flash chromatographyusing a mixture of ethyl acetate-hexanes as the eluting medium to affordthe above mentioned product.

Synthesis of 4-(4-bromomethylphenyl)butyl tert-butyldimethylsilyl ether

To a 50 ml round bottom flask is charged 4-(4-methylphenyl)butyltert-butyldimethylsilyl ether (0.25 g, 0.89 mmol), N-bromosuccinimide(0.158 g, 0.89 mmol), benzoyl peroxide (2.17 mg, 0.0089 mmol) and 10 mlcarbon tetrachloride. This mixture is refluxed overnight after which itis cooled and filtered. The filtrate is concentrated and the resultingcrude residue purified by flash chromatography in ethyl acetate-hexanesto afford the product.

Synthesis of 4-(4-tert-butyldimethylsilyloxybutyl)phenylacetic acid

4-(4-bromomethylphenyl)butyl tert-butyldimethylsilyl ether (0.2 g, 0.561mmol) in dry ether is added dropwise to Mg turnings (13.77 mg, 0.561mmol). A few crystals of iodine are then added to initiate the reactionand the mixture is refluxed overnight under nitrogen atmosphere. Thesolution is then cooled and CO₂ gas is bubbled into it for 10 minutes.Stirring is continued for a further 2 hours after which water is addedto the reaction mixture. The mixture is then extracted with ethylacetate, washed and dried. After removing the organic solvent underreduced pressure the crude is purified by flash chromatography (silicagel; ethyl acetate/hexanes) to yield the desired product.

Synthesis of 2-hydroxyethyl-4-(4-tert-butyldimethylsilyloxybutyl)benzene

4-(4-tert-butyldimethylsilyloxybutyl)phenylacetic acid (0.25 g, 0.775mmol) dissolved in dry ether is added dropwise to a suspension oflithium aluminum hydride in ether (44.2 mg, 1.16 mmol). The reactionmixture is stirred for 5 hours after which water (45 μl), NaOH (15%solution, 45 μl) and water (135 μl) are successively added and thereaction mixture is stirred for a further 30 minutes. The resultingprecipitate is filtered and washed with ether. The ether filtrate isthen washed with water and dried. After concentrating the ether, theproduct obtained is purified by flash chromatography (silica gel; ethylacetate/hexanes)

Synthesis of4-(2-(4-(4-tert-butyldimethylsilyloxybutyl)phenyl)ethoxy)quinazoline

2-hydroxyethyl-4-(4-tert-butyldimethylsilyloxybutyl)benzene (0.3 g, 0.97mmol) is dissolved in dry tetrahydrofuran and to it is added sodiumhydride (24 mg, 1 mmol). The resulting solution is stirred at roomtemperature for 30 minutes after which 4-chloroquinazoline (0.164 g, 1mmol) is added to the above solution. The solution is then stirred for 6hours after which water is added to the mixture. The solution is thenextracted in dichloromethane. The organic layer is washed, dried andthen concentrated to yield the crude product which is purified by flashchromatography (silica gel; ethyl acetate/hexanes) to give the product.

Synthesis of 4-(2-(4-(4-hydroxybutyl)phenyl)ethoxy)quinazoline

To 4-(2-(4-(4-tert-butyldimethylsilyloxybutyl)phenyl)ethoxy)quinazoline(0.4 g, 0.916 mmol) is added tetrabutylammonium fluoride solution (1MTBAF in THF, 4.58 ml, 4.58 mmol). The solution is stirred for 2 hoursafter which water is added to the reaction and this is extracted inethyl acetate. The organic layer is then washed with water, dried andconcentrated. The residue obtained is purified by flash chromatography(silica gel; ethyl acetate/hexanes)

Synthesis of4-(2-(4-(4-p-toluenesulfonyloxybutyl)phenyl)ethoxy)quinazoline

A 15 ml round bottom flask charged with4-(2-(4-(4-hydroxybutyl)phenyl)ethoxy)quinazoline (0.25 g, 0.77 mmol) isdissolved in pyridine (5 ml). p-Toluenesulfonyl chloride (0.15 g, 0.79mmol) is then added to it and the mixture stirred for 4 hours. Thereaction mixture is diluted with ethyl acetate, washed with 5% coppersulfate solution and then with water and dried. After removing thesolvent on the rotary evaporator the crude is purified by flashchromatography using silica gel (ethyl acetate/hexanes) to give theproduct.

Synthesis of 4-(2-(4-(4-fluorobutyl)phenyl)ethoxy)quinazoline

4-(2-(4-(4-p-toluenesulfonyloxybutyl)phenyl)ethoxy)quinazoline (0.3 g,0.63 mmol) is added to a solution of potassium fluoride/kryptofix 222 in5 ml THF (1:1 ratio, 3.15 mmol each). After stirring at room temperaturefor 15 minutes the solution is then refluxed for 20 minutes. It is thencooled and water is added to it. The solution is then extracted indichloromethane and washed with water and dried. The crude product ispurified by silica gel flash chromatography (ethyl acetate/hexanes) toafford the product.

Synthesis of 4-(2-(4-(4-[¹⁸F]-fluorobutyl)phenyl)ethoxy)quinazoline

To a 5 ml reaction vial containing 100 mCi of ¹⁸F in 300 mg of ¹⁸O wateris added a 1 ml solution consisting of 10 mg of Kryptofix, 1 mgpotassium carbonate, 0.005 ml water and 0.95 ml acetonitrile. The vialis heated to remove all the solvents and dry acetonitrile (1 ml) isadded to the vial. This is also removed by evaporation.4-(2-(4-(4-p-toluenesulfonyloxybutyl)phenyl)ethoxy)quinazoline (5 mg) inacetonitrile is then added to it. The vial is sealed and heated for 30minutes at 100° C. The mixture is diluted with dichloromethane andpassed through a Sep-Pak and eluted with tetrahydrofuran. The solvent isevaporated to get the above mentioned compound.

Synthesis of 4-Chloro-2-quinazolone

2-Cyanophenyl isocyanate (5 g, 34.7 mmol) is suspended in di-n-butylether. HCl gas is then passed into the suspension at 80° C. for 7 hours.The resulting precipitate is filtered, dried and recrystallized fromchlorobenzene to afford the above product.

Synthesis of 4-(2-(4-tert-butylphenyl)-ethoxy)-2-quinazolone

2-(4-tert-butylphenyl)ethanol (0.3 g, 1.68 mmol) is dissolved in drytetrahydrofuran (7 ml) and to it is added sodium hydride (48.5 mg, 2.02mmol). The resulting solution is stirred at room temperature for 30minutes after which 4-chloro-2-quinazolone (0.302 g, 1.68 mmol) is addedto the above solution. The solution is then stirred for 6 hours afterwhich water is added to the mixture. The solution is then extracted indichloromethane. The organic layer is washed, dried and thenconcentrated to yield the crude product which is purified by flashchromatography (silica gel; ethyl acetate/hexanes) to give the product.

Synthesis of4-(2-(4-tert-butylphenyl)-ethoxy)-2-(trifluoromethanesulfonyloxy)-quinazoline

4-(2-(4-tert-butylphenyl)-ethoxy)-2-quinazolone (0.25 g, 0.775 mmol) isdissolved in dichloromethane (5 ml) and trifluoromethanesulfonicanhydride (0.328 g, 1.16 mmol) and diisopropylethyl amine (0.3 g, 2.32mmol) is added to it. The reaction is stirred overnight after which itis further diluted with dichloromethane and washed with water. Theorganic layer is then dried and concentrated. The crude product obtainedis isolated by flash chromatography (silica gel; ethyl acetate/hexanes).

Synthesis of 4-(2-(4-tert-butylphenyl)-ethoxy)-2-fluoro-quinazoline

A 15 ml round bottom flask is charged with4-(2-(4-tert-butylphenyl)-ethoxy)-2-(trifluoromethanesulfonyloxy)-quinazoline(0.3 g, 0.66 mmol). Tetrabutylammonium fluoride solution (1M in THF, 3.3ml, 3.3 mmol) is then added to it and the solution refluxed for 60minutes. The mixture is then cooled and water is added to it. It is thenextracted with dichloromethane, washed with water and dried. The crudeobtained after concentration is purified by silica gel flashchromatography (ethyl acetate/hexanes) to obtain the desired compound.

Synthesis of4-(2-(4-tert-butylphenyl)-ethoxy)-2-[¹⁸F]-fluoro-quinazoline

Aqueous ¹⁸F (16 mCi, 0.1 ml) is added to a vacutainer containing 5 μl oftetrabutylammonium hydroxide (40% wt sol. in water). The mixture isconcentrated under nitrogen in an oil bath at 100 C and 250 μl ofacetonitrile is added and this too is concentrated under nitrogen. Theprocedure is repeated twice and then 100 μl of acetonitrile is added toit and the contents subjected to vacuum. Without letting go dry THF isthen added to it followed by 5 mg of4-(2-(4-tert-butylphenyl)-ethoxy)-2-(trifluoromethanesulfonyloxy)-quinazoline.The mixture is then heated in an oil bath at 70° C. for 30 minutes. Thisis then diluted with water, applied to a C18 Sep-Pak, rinsed with waterand eluted with acetonitrile to get the above mentioned compound.

Synthesis of 6-Nitro-4(3H)-quinazolone

A mixture of 5-nitroanthranilic acid (2 g, 14.6 mmol) and formamide (2.9ml, 72 mmol) is irradiated at 150 C in a microwave (power: 60 W) untilTLC shows completion of reaction (20 minutes). After cooling, thereaction mixture is rinsed with ethyl acetate and evaporated underreduced pressure. The crude is purified by flash chromatography (silicagel; ethyl acetate/hexanes) to give the above product.

Synthesis of 6-Nitro-4-chloroquinoline

6-Nitro-4(3H)-quinazolone (1 g, 5.23 mmol) and POCl₃ (7.1 ml) are mixedtogether and irradiated at 100 C (power: 70 W) for 10 minutes. The POCl₃is evaporated in vacuo and the residue is dissolved in ethyl acetate andwashed with saturated NaHCO₃, dried and concentrated. It is purified byflash chromatography (silica gel; ethyl acetate/hexanes) to give theabove product.

Synthesis of 6-Nitro-4-(2-(4-tert-butylphenyl)ethoxy)quinazoline

2-(4-tert-butylphenyl)ethanol (1.0 g, 5.59 mmol) is dissolved in drytetrahydrofuran (7 ml) and to it is added sodium hydride (48.5 mg, 2.02mmol). The resulting solution is stirred at room temperature for 30minutes after which 6-Nitro-4-chloroquinazoline (1.17 g, 5.6 mmol) isadded to the above solution. The solution is then stirred for 6 hoursafter which water is added to the mixture. The solution is thenextracted in dichloromethane. The organic layer is washed, dried andthen concentrated to yield the crude product which is purified by flashchromatography (silica gel; ethyl acetate/hexanes) to give the product.

Synthesis of 6-Fluoro-4-(2-(4-tert-butylphenyl)ethoxy)quinazoline

To a 25 ml round bottom flask is added potassium fluoride (82.6 mg, 1.42mmol) and kryptofix 222 (0.53 g, 1.42 mmol). The above mixture isstirred in THF for 20 minutes after which6-Nitro-4-(2-(4-tert-butylphenyl)ethoxy)quinazoline (0.1 g, 0.284 mmol)is added to it. The solution is refluxed for 30 minutes after which itis cooled and water is added to it. It is then extracted indichloromethane, washed with water and dried. Purification by flashchromatography (silica gel; ethyl acetate/hexanes) gives the abovecompound.

Synthesis of 6-[¹⁸F]-Fluoro-4-(2-(4-tert-butylphenyl)ethoxy)quinazoline

To a 5 ml reaction vial containing 50 mCi of ¹⁸F. in 300 mg of ¹⁸O wateris added a 1 ml solution consisting of 10 mg of Kryptofix, 1 mgpotassium carbonate, 0.005 ml water and 0.95 ml acetonitrile. The vialis heated to remove all the solvents and dry acetonitrile (1 ml) isadded to the vial. This is also removed by evaporation.6-Nitro-4-(2-(4-tert-butylphenyl)ethoxy)quinazoline (5 mg) inacetonitrile is then added to it. The vial is sealed and heated for 30minutes at 100° C. The mixture is diluted with dichloromethane andpassed through a Sep-Pak and eluted with tetrahydrofuran. The solvent isevaporated to get the above mentioned compound

Synthesis of (4-tert-butylphenyl)ethane 1,2 diol

To a 100 ml round bottom flask is added 20 ml tert butanol, 20 ml ofwater and 5.6 g of AD-mix-β. The solution is stirred and cooled to 0° C.tert-butyl styrene (0.64 g, 4 mmol) is added to the mixture and theresulting solution is stirred overnight at 0 C. Solid sodium sulfite (6g) is added and the mixture stirred for an additional 30 minutes. Thesolution is then extracted in ethyl acetate, washed with water anddried. The crude is then purified by flash chromatography (silica gel;ethyl acetate/hexanes) to afford the product.

Synthesis of1-tert-butyldimethylsilyloxy-2-hydroxy-2-(4-tertbutylphenyl)ethane

(4-tert-butylphenyl)ethane 1,2 diol (0.5 g, 2.57 mmol) is dissolved inDMF in a 25 ml round bottom flask and to this were added imidazole(0.210 g, 3.09 mmol) and tert-butyldimethylsilyl chloride (0.46 g, 3.09mmol). The mixture is stirred for 6 hours after which it is extracted indichloromethane and the organic layer washed with water and dried.Purification by flash chromatography (silica gel; ethyl acetate/hexanes)affords the above mentioned product.

Synthesis of1-tert-butyldimethylsilyloxy-2-tetrahydropyranyloxy-2-(4-tertbutylphenyl)ethane

1-Tert-butyldimethylsilyloxy-2-hydroxy-2-(4-tert-butylphenyl)ethane (0.5g, 1.622 mmol) is dissolved in dichloromethane and to it is addeddihydropyran (0.163 g, 1.94 mmol) and toluenesulfonic acid (33 mg, 0.194mmol). The reaction is stirred for 2 hours after which the mixture iswashed with water and dried. The crude residue obtained afterconcentration is purified by flash chromatography (silica gel; ethylacetate/hexanes) to obtain the product.

Synthesis of1-hydroxy-2-tetrahydropyranyloxy-2-(4-tert-butylphenyl)ethane

To1-tert-butyldimethylsilyloxy-2-tetrahydropyranyloxy-2-(4-tertbutylphenyl)ethane(0.4 g, 1.01 mmol) is added tetrabutylammonium fluoride solution (1MTBAF in THF, 5 ml, 5.0 mmol). The solution is stirred for 2 hours afterwhich water is added to the reaction and this is extracted in ethylacetate. The organic layer is then washed with water, dried andconcentrated. The residue obtained is purified by flash chromatography(silica gel; ethyl acetate/hexanes).

Synthesis of4-(2-tetrahydropyranyloxy-2-(4-tert-butylphenyl)ethoxy)quinazoline

1-Hydroxy-2-tetrahydropyranyloxy-2-(4-tert-butylphenyl)ethane (0.3 g,1.07 mmol) is dissolved in dry tetrahydrofuran (7 ml) and to it is addedsodium hydride (30.96 mg, 1.29 mmol). The resulting solution is stirredat room temperature for 30 minutes after which 4-chloroquinazoline(0.175 g, 1.07 mmol) is added to the above solution. The solution isthen stirred for 6 hours after which water is added to the mixture. Thesolution is then extracted in dichloromethane. The organic layer iswashed, dried and then concentrated to yield the crude product which ispurified by flash chromatography (silica gel; ethyl acetate/hexanes) togive the product.

Synthesis of 4-(2-hydroxy-2-(4-tert-butylphenyl)ethoxy)quinazoline

4-(2-tetrahydropyranyloxy-2-(4-tert-butylphenyl)ethoxy)quinazoline (0.25g, 0.615 mmol) is dissolved in 5 ml ethanol andpyridinium-p-toluenesulfonate (15.4 mg, 0.061 mmol) is added to it. Thesolution is heated to 55° C. and stirred at that temperature for 4hours. The ethanol is removed and the crude is purified by flashchromatography (silica gel; ethyl acetate/hexanes).

Synthesis of4-(2-p-toluenesulfonyloxy-2-(4-tert-butylphenyl)ethoxy)quinazoline

A 15 ml round bottom flask is charged with4-(2-hydroxy-2-(4-tert-butylphenyl)ethoxy)quinazoline (0.25 g, 0.77mmol) is dissolved in pyridine (5 ml). p-Toluenesulfonyl chloride (0.15g, 0.79 mmol) is then added to it and the mixture stirred for 4 hours.The reaction mixture is diluted with ethyl acetate, washed with 5%copper sulfate solution and then with water and dried. After removingthe solvent on the rotary evaporator the crude is purified by flashchromatography using silica gel (ethyl acetate/hexanes) to give theproduct.

Synthesis of 4-(2-fluoro-2-(4-tert-butylphenyl)ethoxy)quinazoline

A 15 ml round bottom flask is charged with4-(2-p-toluenesulfonyloxy-2-(4-tert-butylphenyl)ethoxy)quinazoline (0.3g, 0.84 mmol). Tetrabutylammonium fluoride solution (1M in THF, 4.2 ml,4.2 mmol) is then added to it and the solution is heated at reflux for60 minutes. The mixture is then cooled and water is added to it. It isthen extracted with dichloromethane, washed with water and dried. Thecrude obtained after concentration is purified by silica gel flashchromatography (ethyl acetate/hexanes) to obtain the desired compound.

Synthesis of 4-(2-[¹⁸F]-fluoro-2-(4-tert-butylphenyl)ethoxy)quinazoline

Aqueous ¹⁸F (16 mCi, 0.1 ml) is added to a vacutainer containing 5 μl oftetrabutylammonium hydroxide (40% wt sol. in water). The mixture isconcentrated under nitrogen in an oil bath at 100° C. and 250 μl ofacetonitrile is added and this too is concentrated under nitrogen. Theprocedure is repeated twice and then 100 μl of acetonitrile is added toit and the contents subjected to vacuum. Without letting go dry THF isthen added to it followed by 5 mg of4-(2-p-toluenesulfonyloxy-2-(4-tert-butylphenyl)ethoxy)quinazoline. Themixture is then heated in an oil bath at 70° C. for 30 minutes. This isthen diluted with water, applied to a C18 Sep-Pak, rinsed with water andeluted with acetonitrile to get the above mentioned compound.

It will be evident to one skilled in the art that the present disclosureis not limited to the foregoing illustrative examples, and that it canbe embodied in other specific forms without departing from the essentialattributes thereof. It is therefore desired that the examples beconsidered in all respects as illustrative and not restrictive,reference being made to the appended claims, rather than to theforegoing examples, and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to be embracedtherein.

What is claimed is:
 1. A method for synthesizing a compound, comprising:reacting a precursor species having the following structure,

wherein R³ is C₁₋₆ alkyl substituted with a hydroxyl group, alkoxysubstituted with a hydroxyl group, or alkoxyalkyl substituted with ahydroxyl group, in the presence of p-toluenesulfonyl chloride, toproduce a compound having the following structure,

wherein R⁴ is C₁₋₆ alkyl substituted with a tosyl group, alkoxysubstituted with a tosyl group, or alkoxyalkyl substituted with a tosylgroup.
 2. The method of claim 1, further comprising: reacting thecompound in the presence of a ¹⁸F-containing species to produce acontrast agent comprising ¹⁸F.
 3. The method of claim 1, wherein theprecursor species has the following structure,


4. The method of claim 1, wherein the compound has the followingstructure,


5. The method of claim 1, further comprising: reacting a species havingthe following structure,

wherein R² is C₁₋₆ alkyl substituted with a protected hydroxyl group,alkoxy substituted with a protected hydroxyl group, or alkoxyalkylsubstituted with protected hydroxyl group, the protected hydroxyl groupcomprising a trialkylsilyl group, in the presence of tetraalkylammoniumfluoride, to produce the precursor species.
 6. The method of claim 5,wherein the species has the following structure,


7. The method of claim 5, further comprising: reacting, via anetherification reaction, a heterocyclic species having the followingstructure,

wherein R¹ is chloro or a hydroxyl group, with a substituted phenylspecies having the following structure,

wherein R² is C₁₋₆ alkyl substituted with a protected hydroxyl group,alkoxy substituted with a protected hydroxyl group, or alkoxyalkylsubstituted with a protected hydroxyl group, the protected hydroxylgroup comprising a trialkylsilyl group.
 8. The method of claim 7,wherein the heterocyclic species has the following structure,


9. The method of claim 7, wherein the substituted phenyl species has thefollowing structure,


10. A method for synthesizing a contrast agent, comprising: reacting acompound having the following structure,

wherein R⁴ is C₁₋₆ alkyl substituted with a tosyl group, alkoxysubstituted with a tosyl group, or alkoxyalkyl substituted with a tosylgroup, in the presence of a ¹⁸F-containing species to produce a contrastagent comprising ¹⁸F.
 11. A method for synthesizing a contrast agent,comprising: reacting a precursor compound having the structure:

in the presence of a ¹⁸F-containing species to produce a contrast agentcomprising the structure:


12. The method of claim 11, wherein the precursor compound is formed viareaction of p-toluenesulfonyl chloride with a hydroxyl-containingcompound comprising the structure:


13. The method of claim 12, wherein the hydroxyl-containing compound isformed via reaction of tetraalkylammonium fluoride with a speciescomprising the structure:


14. The method of claim 13, wherein the species is formed via reactionwith a heterocyclic species comprising the structure:

with a substituted phenyl species comprising the structure: